CWE-297

The getCN function in Apache Axis 1.4 and earlier does not properly verify that the server hostname matches a domain name in the subject's Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via a certificate with a subject that specifies a common name in a field that is not the CN field. NOTE: this issue exists because of an incomplete fix for CVE-2012-5784.

The Serf RA layer in Apache Subversion 1.4.0 through 1.7.x before 1.7.18 and 1.8.x before 1.8.10 does not properly handle wildcards in the Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof servers via a crafted certificate.

A weakness was found in postgresql-jdbc before version 42.2.5. It was possible to provide an SSL Factory and not check the host name if a host name verifier was not provided to the driver. This could lead to a condition where a man-in-the-middle attacker could masquerade as a trusted server by providing a certificate for the wrong host, as long as it was signed by a trusted CA.

Apache Sling Commons Messaging Mail provides a simple layer on top of JavaMail/Jakarta Mail for OSGi to send mails via SMTPS. To reduce the risk of "man in the middle" attacks additional server identity checks must be performed when accessing mail servers. For compatibility reasons these additional checks are disabled by default in JavaMail/Jakarta Mail. The SimpleMailService in Apache Sling Commons Messaging Mail 1.0 lacks an option to enable these checks for the shared mail session. A user could enable these checks nevertheless by accessing the session via the message created by SimpleMessageBuilder and setting the property mail.smtps.ssl.checkserveridentity to true. Apache Sling Commons Messaging Mail 2.0 adds support for enabling server identity checks and these checks are enabled by default. - https://javaee.github.io/javamail/docs/SSLNOTES.txt - https://javaee.github.io/javamail/docs/api/com/sun/mail/smtp/package-summary.html - https://github.com/eclipse-ee4j/mail/issues/429

libcurl did not check the server certificate of TLS connections done to a host specified as an IP address, when built to use mbedTLS. libcurl would wrongly avoid using the set hostname function when the specified hostname was given as an IP address, therefore completely skipping the certificate check. This affects all uses of TLS protocols (HTTPS, FTPS, IMAPS, POPS3, SMTPS, etc).

Incorrect validation of the TLS SNI hostname in osquery versions after 2.9.0 and before 4.2.0 could allow an attacker to MITM osquery traffic in the absence of a configured root chain of trust.

A flaw was found in rsync in versions since 3.2.0pre1. Rsync improperly validates certificate with host mismatch vulnerability. A remote, unauthenticated attacker could exploit the flaw by performing a man-in-the-middle attack using a valid certificate for another hostname which could compromise confidentiality and integrity of data transmitted using rsync-ssl. The highest threat from this vulnerability is to data confidentiality and integrity. This flaw affects rsync versions before 3.2.4.

PJSIP is a free and open source multimedia communication library written in C language implementing standard based protocols such as SIP, SDP, RTP, STUN, TURN, and ICE. In version 2.10 and earlier, PJSIP transport can be reused if they have the same IP address + port + protocol. However, this is insufficient for secure transport since it lacks remote hostname authentication. Suppose we have created a TLS connection to `sip.foo.com`, which has an IP address `100.1.1.1`. If we want to create a TLS connection to another hostname, say `sip.bar.com`, which has the same IP address, then it will reuse that existing connection, even though `100.1.1.1` does not have certificate to authenticate as `sip.bar.com`. The vulnerability allows for an insecure interaction without user awareness. It affects users who need access to connections to different destinations that translate to the same address, and allows man-in-the-middle attack if attacker can route a connection to another destination such as in the case of DNS spoofing.

Certificates.java in Not Yet Commons SSL before 0.3.15 does not properly verify that the server hostname matches a domain name in the subject's Common Name (CN) field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.

A flaw was found in Keycloak in versions before 10.0.0, where it does not perform the TLS hostname verification while sending emails using the SMTP server. This flaw allows an attacker to perform a man-in-the-middle (MITM) attack.

The (1) HttpResource and (2) FileBackedHttpResource implementations in Shibboleth Identity Provider (IdP) before 2.4.1 and OpenSAML Java 2.6.2 do not verify that the server hostname matches a domain name in the subject's Common Name (CN) or subjectAltName field of the X.509 certificate, which allows man-in-the-middle attackers to spoof SSL servers via an arbitrary valid certificate.

Splunk Enterprise peers in Splunk Enterprise versions before 9.0 and Splunk Cloud Platform versions before 8.2.2203 did not validate the TLS certificates during Splunk-to-Splunk communications by default. Splunk peer communications configured properly with valid certificates were not vulnerable. However, an attacker with administrator credentials could add a peer without a valid certificate and connections from misconfigured nodes without valid certificates did not fail by default. For Splunk Enterprise, update to Splunk Enterprise version 9.0 and Configure TLS host name validation for Splunk-to-Splunk communications (https://docs.splunk.com/Documentation/Splunk/9.0.0/Security/EnableTLSCertHostnameValidation) to enable the remediation.

An issue was discovered in the Bouncy Castle Crypto Package For Java before BC TLS Java 1.0.19 (ships with BC Java 1.78, BC Java (LTS) 2.73.6) and before BC FIPS TLS Java 1.0.19. When endpoint identification is enabled in the BCJSSE and an SSL socket is created without an explicit hostname (as happens with HttpsURLConnection), hostname verification could be performed against a DNS-resolved IP address in some situations, opening up a possibility of DNS poisoning.

In Java-WebSocket less than or equal to 1.4.1, there is an Improper Validation of Certificate with Host Mismatch where WebSocketClient does not perform SSL hostname validation. This has been patched in 1.5.0.

The Socket Appender in Apache Log4j Core versions 2.0-beta9 through 2.25.2 does not perform TLS hostname verification of the peer certificate, even when the verifyHostName https://logging.apache.org/log4j/2.x/manual/appenders/network.html#SslConfiguration-attr-verifyHostName configuration attribute or the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.html#log4j2.sslVerifyHostName system property is set to true. This issue may allow a man-in-the-middle attacker to intercept or redirect log traffic under the following conditions: * The attacker is able to intercept or redirect network traffic between the client and the log receiver. * The attacker can present a server certificate issued by a certification authority trusted by the Socket Appender’s configured trust store (or by the default Java trust store if no custom trust store is configured). Users are advised to upgrade to Apache Log4j Core version 2.25.3, which addresses this issue. As an alternative mitigation, the Socket Appender may be configured to use a private or restricted trust root to limit the set of trusted certificates.

Mifos-Mobile Android Application for MifosX is an Android Application built on top of the MifosX Self-Service platform. Mifos-Mobile before commit e505f62 disables HTTPS hostname verification of its HTTP client. Additionally it accepted any self-signed certificate as valid. Hostname verification is an important part when using HTTPS to ensure that the presented certificate is valid for the host. Disabling it can allow for man-in-the-middle attacks. Accepting any certificate, even self-signed ones allows man-in-the-middle attacks. This problem is fixed in mifos-mobile commit e505f62.

An exploitable vulnerability exists in the remote control functionality of Circle with Disney running firmware 2.0.1. SSL certificates for specific domain names can cause the rclient daemon to accept a different certificate than intended. An attacker can host an HTTPS server with this certificate to trigger this vulnerability.

PKId in Juniper Junos OS before 12.1X44-D52, 12.1X46 before 12.1X46-D37, 12.1X47 before 12.1X47-D30, 12.3 before 12.3R12, 12.3X48 before 12.3X48-D20, 13.3 before 13.3R10, 14.1 before 14.1R8, 14.1X53 before 14.1X53-D40, 14.2 before 14.2R7, 15.1 before 15.1R4, 15.1X49 before 15.1X49-D20, 15.1X53 before 15.1X53-D60, and 16.1 before 16.1R1 allow remote attackers to bypass an intended certificate validation mechanism via a self-signed certificate with an Issuer name that matches a valid CA certificate enrolled in Junos.

An exploitable vulnerability exists in the remote control functionality of Circle with Disney running firmware 2.0.1. SSL certificates for specific domain names can cause the goclient daemon to accept a different certificate than intended. An attacker can host an HTTPS server with this certificate to trigger this vulnerability.

An issue was discovered in the methods push.lite.avtech.com.AvtechLib.GetHttpsResponse and push.lite.avtech.com.Push_HttpService.getNewHttpClient in AVTECH EagleEyes 2.0.0. The methods set ALLOW_ALL_HOSTNAME_VERIFIER, bypassing domain validation.

Potentially, SAP Cloud Connector, version - 2.0 communication with the backend is accepted without sufficient validation of the certificate.

Jenkins View26 Test-Reporting Plugin 1.0.7 and earlier does not perform hostname validation when connecting to the configured View26 server that could be abused using a man-in-the-middle attack to intercept these connections.

Jenkins SmallTest Plugin 1.0.4 and earlier does not perform hostname validation when connecting to the configured View26 server that could be abused using a man-in-the-middle attack to intercept these connections.

An improper certificate validation vulnerability [CWE-295] in FortiManager 7.0.1 and below, 6.4.6 and below; FortiAnalyzer 7.0.2 and below, 6.4.7 and below; FortiOS 6.2.x and 6.0.x; FortiSandbox 4.0.x, 3.2.x and 3.1.x may allow a network adjacent and unauthenticated attacker to man-in-the-middle the communication between the listed products and some external peers.

When doing SSH-based transfers using either SCP or SFTP, and setting the known_hosts file, libcurl could still mistakenly accept connecting to hosts *not present* in the specified file if they were added as recognized in the libssh *global* known_hosts file.

An issue discovered in casdoor v1.636.0 allows attackers to obtain sensitive information via the ssh.InsecureIgnoreHostKey() method.

ZITADEL provides users the possibility to use Time-based One-Time-Password (TOTP) and One-Time-Password (OTP) through SMS and Email. While ZITADEL already gives administrators the option to define a `Lockout Policy` with a maximum amount of failed password check attempts, there was no such mechanism for (T)OTP checks. This issue has been patched in version 2.50.0.

KEPServerEX does not properly validate certificates from clients which may allow unauthenticated users to connect.

The fix for CVE-2025-68161 https://logging.apache.org/security.html#CVE-2025-68161 was incomplete: it addressed hostname verification only when enabled via the log4j2.sslVerifyHostName https://logging.apache.org/log4j/2.x/manual/systemproperties.html#log4j2.sslVerifyHostName system property, but not when configured through the verifyHostName https://logging.apache.org/log4j/2.x/manual/appenders/network.html#SslConfiguration-attr-verifyHostName attribute of the <Ssl> element. Although the verifyHostName configuration attribute was introduced in Log4j Core 2.12.0, it was silently ignored in all versions through 2.25.3, leaving TLS connections vulnerable to interception regardless of the configured value. A network-based attacker may be able to perform a man-in-the-middle attack when all of the following conditions are met: * An SMTP, Socket, or Syslog appender is in use. * TLS is configured via a nested <Ssl> element. * The attacker can present a certificate issued by a CA trusted by the appender's configured trust store, or by the default Java trust store if none is configured. This issue does not affect users of the HTTP appender, which uses a separate verifyHostname https://logging.apache.org/log4j/2.x/manual/appenders/network.html#HttpAppender-attr-verifyHostName attribute that was not subject to this bug and verifies host names by default. Users are advised to upgrade to Apache Log4j Core 2.25.4, which corrects this issue.

A flaw was found in Kroxylicious. When establishing the connection with the upstream Kafka server using a TLS secured connection, Kroxylicious fails to properly verify the server's hostname, resulting in an insecure connection. For a successful attack to be performed, the attacker needs to perform a Man-in-the-Middle attack or compromise any external systems, such as DNS or network routing configuration. This issue is considered a high complexity attack, with additional high privileges required, as the attack would need access to the Kroxylicious configuration or a peer system. The result of a successful attack impacts both data integrity and confidentiality.

An issue was discovered in Ada Web Server 20.0. When configured to use SSL (which is not the default setting), the SSL/TLS used to establish connections to external services is done without proper hostname validation. This is exploitable by man-in-the-middle attackers.

A flaw was found in Keycloak. By setting a verification policy to 'ALL', the trust store certificate verification is skipped, which is unintended.

IBM OpenPages with Watson 8.3 and 9.0  could allow a remote attacker to spoof mail server identity when using SSL/TLS security. An attacker could exploit this vulnerability to gain access to sensitive information disclosed through email notifications generated by OpenPages or disrupt notification delivery.

IBM Storage Defender 2.0.0 through 2.0.7 on-prem defender-sensor-cmd CLI does not validate server name during registration and unregistration operations which could expose sensitive information to an attacker with access to the system.

Hostname verification bypass issue in Apache Ranger NiFiRegistryClient/NiFiClient is reported in Apache Ranger versions <= 2.7.0. Users are recommended to upgrade to version 2.8.0, which fixes this issue.

The vulnerability have been reported to affect earlier versions of Helpdesk. If exploited, this improper certificate validation vulnerability could allow an attacker to spoof a trusted entity by interfering in the communication path between the host and client. QNAP has already fixed the issue in Helpdesk 3.0.3 and later.

Hostname verification in Apache ZooKeeper ZKTrustManager falls back to reverse DNS (PTR) when IP SAN validation fails, allowing attackers who control or spoof PTR records to impersonate ZooKeeper servers or clients with a valid certificate for the PTR name. It's important to note that attacker must present a certificate which is trusted by ZKTrustManager which makes the attack vector harder to exploit. Users are recommended to upgrade to version 3.8.6 or 3.9.5, which fixes this issue by introducing a new configuration option to disable reverse DNS lookup in client and quorum protocols.

The mobile application (com.transsnet.store) has a man-in-the-middle attack vulnerability, which may lead to code injection risks.

Improper Validation of Certificate with Host Mismatch vulnerability in Apache Thrift. This issue affects Apache Thrift: before 0.23.0. Users are recommended to upgrade to version 0.23.0, which fixes the issue.

Dell EMC NetWorker versions 19.1.x, 19.1.0.x, 19.1.1.x, 19.2.x, 19.2.0.x, 19.2.1.x 19.3.x, 19.3.0.x, 19.4.x, 19.4.0.x, 19.5.x,19.5.0.x, 19.6 and 19.6.0.1 and 19.6.0.2 contain an Improper Validation of Certificate with Host Mismatch vulnerability in Rabbitmq port 5671 which could allow remote attackers to spoof certificates.

Opencast before versions 8.9 and 7.9 disables HTTPS hostname verification of its HTTP client used for a large portion of Opencast's HTTP requests. Hostname verification is an important part when using HTTPS to ensure that the presented certificate is valid for the host. Disabling it can allow for man-in-the-middle attacks. This problem is fixed in Opencast 7.9 and Opencast 8.8 Please be aware that fixing the problem means that Opencast will not simply accept any self-signed certificates any longer without properly importing them. If you need those, please make sure to import them into the Java key store. Better yet, get a valid certificate.

Improper Validation of Certificate with Host Mismatch vulnerability in Gotham Chat IRC helper of Palantir Gotham allows A malicious attacker in a privileged network position could abuse this to perform a man-in-the-middle attack. A successful man-in-the-middle attack would allow them to intercept, read, or modify network communications to and from the affected service. This issue affects: Palantir Palantir Gotham Chat IRC helper versions prior to 30221005.210011.9242.

Improper Validation of Certificate with Host Mismatch vulnerability in Apache Thrift. This issue affects Apache Thrift: before 0.23.0. Users are recommended to upgrade to version 0.23.0, which fixes the issue.

Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_cert and public_key modules) allows a DNS nameConstraints bypass via subject CommonName fallback in TLS hostname verification. Two flaws combine to allow a subordinate CA whose DNS nameConstraints are restricted (e.g. permitted;DNS:allowed.example.com) to issue a leaf certificate that an OTP TLS client accepts as a valid identity for an out-of-scope hostname (e.g. victim.example.com): First, pubkey_cert:validate_names/6 in lib/public_key/src/pubkey_cert.erl only checks SAN DNS entries against nameConstraints. Per RFC 5280, a permitted DNS subtree only restricts certificates that contain a DNS-typed name. A leaf with no subjectAltName therefore trivially satisfies any permitted;DNS:... constraint regardless of its subject commonName. Second, public_key:pkix_verify_hostname/3 in lib/public_key/src/public_key.erl falls back to the subject commonName when no subjectAltName is present, extracting id-at-commonName attributes as presented IDs and matching them against the reference hostname. The strict pkix_verify_hostname_match_fun(https) matcher does not suppress this fallback. The result is that path validation accepts a CN-only leaf under a DNS-constrained intermediate (no SAN means the nameConstraints are not triggered), and hostname verification then accepts it via the CN fallback. The bypass is reachable from stock ssl:connect with verify_peer, a trusted CA, SNI, and the canonical strict https hostname matcher. This issue affects OTP from OTP 19.3 before OTP 26.2.5.21, 27.3.4.12, 28.5.0.1, and 29.0.1 corresponding to public_key from 1.4 before 1.15.1.7, 1.17.1.3, 1.20.3.1, and 1.21.1.

Dell NetWorker, contains an Improper Validation of Certificate with Host Mismatch vulnerability in Rabbitmq port which could disallow replacing CA signed certificates.

The Uniffle HTTP client is configured to trust all SSL certificates and disables hostname verification by default. This insecure configuration exposes all REST API communication between the Uniffle CLI/client and the Uniffle Coordinator service to potential Man-in-the-Middle (MITM) attacks. This issue affects all versions from before 0.10.0. Users are recommended to upgrade to version 0.10.0, which fixes the issue.

Allow attackers to intercept or falsify data exchanges between the client and the server

It was discovered that the sls-logging was not verifying hostnames in TLS certificates due to a misuse of the javax.net.ssl.SSLSocketFactory API. A malicious attacker in a privileged network position could abuse this to perform a man-in-the-middle attack. A successful man-in-the-middle attack would allow them to intercept, read, or modify network communications to and from the affected service. In the case of AtlasDB, the vulnerability was mitigated by other network controls such as two-way TLS when deployed as part of a Palantir platform. Palantir still recommends upgrading to a non-vulnerable version out of an abundance of caution.

It was discovered that the Magritte-ftp was not verifying hostnames in TLS certificates due to a misuse of the javax.net.ssl.SSLSocketFactory API. A malicious attacker in a privileged network position could abuse this to perform a man-in-the-middle attack. A successful man-in-the-middle attack would allow them to intercept, read, or modify network communications to and from the affected service. In the case of a successful man in the middle attack on magritte-ftp, an attacker would be able to read and modify network traffic such as authentication tokens or raw data entering a Palantir Foundry stack.

Improper Validation of Certificate with Host Mismatch vulnerability in Hitachi Device Manager on Windows, Linux (Device Manager Server, Device Manager Agent, Host Data Collector components) allows Man in the Middle Attack.This issue affects Hitachi Device Manager: before 8.8.5-02.

The Couchbase .NET SDK (client library) before 3.7.1 does not properly enable hostname verification for TLS certificates. In fact, the SDK was also using IP addresses instead of hostnames due to a configuration option that was incorrectly enabled by default.

It was discovered that the sls-logging was not verifying hostnames in TLS certificates due to a misuse of the javax.net.ssl.SSLSocketFactory API. A malicious attacker in a privileged network position could abuse this to perform a man-in-the-middle attack. A successful man-in-the-middle attack would allow them to intercept, read, or modify network communications to and from the affected service.

It was identified that the LDAP client implementation in version 2.1.7 does not verify if the server certificate matches the intended LDAP hostname. While the underlying code validates the certificate chain against a trusted authority, the absence of endpoint identification allows a valid certificate issued for an entirely unrelated host to be improperly accepted. This oversight leaves the connection highly vulnerable to server impersonation and complete connection compromise. The root cause of this vulnerability lies in the incomplete TLS server identity verification within the LDAP client implementation. The attacker requires MITM capability on the network to exploit this vulnerability. This attacker must be able to present a certificate trusted by the client's configured trust store. The hostname verification has been enforced in the new version of the LDAP API

Galaxy FDS Android SDK (XiaoMi/galaxy-fds-sdk-android) version 3.0.8 and prior disable TLS hostname verification when HTTPS is enabled (the default configuration). In GalaxyFDSClientImpl.createHttpClient(), the SDK configures Apache HttpClient with SSLSocketFactory.ALLOW_ALL_HOSTNAME_VERIFIER, which accepts any valid TLS certificate regardless of hostname mismatch. Because HTTPS is enabled by default in FDSClientConfiguration, all applications using the SDK with default settings are affected. This vulnerability allows a man-in-the-middle attacker to intercept and modify SDK communications to Xiaomi FDS cloud storage endpoints, potentially exposing authentication credentials, file contents, and API responses. The XiaoMi/galaxy-fds-sdk-android open source project has reached end-of-life status.

JRuby-OpenSSL is an add-on gem for JRuby that emulates the Ruby OpenSSL native library. Starting in JRuby-OpenSSL version 0.12.1 and prior to version 0.15.4 (corresponding to JRuby versions starting in 9.3.4.0 prior to 9.4.12.1 and 10.0.0.0 prior to 10.0.0.1), when verifying SSL certificates, JRuby-OpenSSL does not verify that the hostname presented in the certificate matches the one the user tries to connect to. This means a man-in-the-middle could just present any valid cert for a completely different domain they own, and JRuby would accept the cert. Anybody using JRuby to make requests of external APIs, or scraping the web, that depends on https to connect securely. JRuby-OpenSSL version 0.15.4 contains a fix for the issue. This fix is included in JRuby versions 10.0.0.1 and 9.4.12.1.

In JetBrains Toolbox App before 2.6 host key verification was missing in SSH plugin

Host name validation for TLS certificates is bypassed when the installed OpenEdge default certificates are used to perform the TLS handshake for a networked connection.  This has been corrected so that default certificates are no longer capable of overriding host name validation and will need to be replaced where full TLS certificate validation is needed for network security.  The existing certificates should be replaced with CA-signed certificates from a recognized certificate authority that contain the necessary information to support host name validation.

Vulnerability in Spring Spring Security. SubjectX500PrincipalExtractor does not correctly handle certain malformed X.509 certificate CN values, which can lead to reading the wrong value for the username. In a carefully crafted certificate, this can lead to an attacker impersonating another user. This issue affects Spring Security: from 7.0.0 through 7.0.4.

The Claude Desktop app gives you Claude Code with a graphical interface built for running multiple sessions side by side. From 1.2581.0 to before 1.4304.0, Claude Desktop's SSH remote development feature verified only whether a hostname existed in ~/.ssh/known_hosts without comparing the server's presented host key against the stored key. This allowed a network-positioned attacker to present an arbitrary SSH host key and have the connection silently accepted, enabling a man-in-the-middle attack on remote development sessions. Successful exploitation required the attacker to be in a network position to intercept SSH traffic (e.g., via ARP spoofing, rogue Wi-Fi, or DNS poisoning) and the target hostname to already have an entry in the victim's known_hosts file. This vulnerability is fixed in 1.4304.0.

Improper Validation of Certificate with Host Mismatch vulnerability in Akınsoft QR Menü allows HTTP Response Splitting. This issue affects QR Menü: from s1.05.05 before v1.05.12.

A improper validation of certificate with host mismatch in Fortinet FortiClientWindows version 7.4.0, versions 7.2.0 through 7.2.6, and 7.0 all versions allow an unauthorized attacker to redirect VPN connections via DNS spoofing or another form of redirection.

An issue was discovered in OpenStack oslo.messaging 1.0.0 through 17.3.0. The oslo.messaging RabbitMQ driver does not perform TLS hostname verification when connecting to the message broker. When ssl_ca_file is configured, the driver enables certificate chain validation but does not pass the expected broker hostname into the underlying TLS stack. Any certificate signed by the deployment CA is accepted regardless of hostname, allowing an attacker who can intercept control-plane traffic to impersonate the RabbitMQ broker and perform a man-in-the-middle attack on RPC and notification traffic. All OpenStack services using oslo.messaging with RabbitMQ over TLS are affected.

Improper host validation in the social login autofill feature in Devolutions Remote Desktop Manager 2026.2.8 allows an attacker to disclose stored social login credentials via a crafted web entry pointing to a provider lookalike domain.

An Improper Validation of Certificate with Host Mismatch vulnerability [CWE-297] in FortiProxy version 7.6.1 and below, version 7.4.8 and below, 7.2 all versions, 7.0 all versions and FortiOS version 7.6.2 and below, version 7.4.8 and below, 7.2 all versions, 7.0 all versions ZTNA proxy may allow an unauthenticated attacker in a man-in-the middle position to intercept and tamper with connections to the ZTNA proxy

Improper Validation of Certificate with Host Mismatch vulnerability in HotelRunner B2B allows HTTP Response Splitting. This issue affects B2B: before 04.06.2025.

### Summary The `server_hostname` TLS SNI check can be bypassed when an existing connection is reused. ### Impact If an application makes multiple requests to the same domain, but with different per-request `server_hostname` parameters, then the later calls may succeed by reusing the existing connection when they should have been rejected due to the TLS SNI check. ### Workaround Disable keep_alive if you need to change the `server_hostname` check between requests. ----- Patch: https://github.com/aio-libs/aiohttp/commit/0ca2b6c28a25726527a8b60f25960262a91ed0e0