CVE-2026-87809

SiYuan before 3.8.4 renders document titles as HTML in the backlink dock tree without escaping markup characters. Attackers can set malicious titles through the rename API or crafted notebooks to execute scripts in the Electron renderer with access to child_process for command execution.

SiYuan versions before 3.8.4 fail to escape bookmark labels imported from notebook files when rendering them in the dock tree. Attackers can craft malicious .sy notebook files with unescaped HTML in bookmark attributes that execute scripts in the Electron renderer with access to child_process for command execution.

SiYuan is a knowledge management system that prior to version 3.7.0 had security vulnerabilities related to 8 ungated APIs that could modify configuration and SQL index. Users with a valid JWT token could access these APIs, leading to unauthorized changes to server state.

SiYuan is an open-source personal knowledge management system. Prior to 3.6.5, the fix for CVE-2026-30869 only added a denylist check but did not address the root cause – a redundant url.PathUnescape() call in serveExport(). An authenticated attacker can use double URL encoding to traverse directories and read arbitrary workspace files including the full SQLite database, kernel log, and all user documents.

SiYuan before version 3.8.2 contains a stored cross-site scripting vulnerability in asset serving due to an incomplete extension blocklist that misses script-capable file types. Attackers can upload files with extensions like .xht, .ehtml, .xsl, .xbl, or .rdf that resolve to executable media types and execute JavaScript to steal API tokens and compromise workspaces.

SiYuan before v3.7.4 fails to validate the packageName parameter in Bazaar install and uninstall endpoints, allowing authenticated administrators to perform path traversal. Attackers with admin access can write arbitrary files or recursively delete directories by supplying crafted packageName values.

SiYuan before v3.7.4 fails to set Content-Disposition and X-Content-Type-Options headers when serving arbitrary file assets, allowing stored cross-site scripting attacks. Authenticated attackers can upload HTML files as assets and execute scripts with full kernel API access when the workspace owner opens the asset link.

SiYuan before 3.7.4 registers Go net/http/pprof debug endpoints including heap and goroutine dumps without authentication when --mode flag is not set to exactly prod. Attackers can access /debug/pprof/heap and related endpoints to extract in-memory secrets including AccessAuthCode and AI provider API keys.

SiYuan kernel versions before 3.7.4 contain an improper restriction of excessive authentication attempts vulnerability in the CheckAuth() middleware. The middleware accepts the API token via an Authorization header or ?token= query parameter, and neither path is protected by CAPTCHA/lockout. An unauthenticated remote attacker can perform unlimited automated guesses of the API token, especially when a short or weak custom token is configured, and upon success gains full RoleAdministrator access enabling arbitrary file operations and SQL queries.

SiYuan versions before v3.7.4 contain a cross-site scripting vulnerability in the unicode2Emoji function that fails to sanitize codepoint branch output. Attackers can craft document icons with hex-encoded markup that executes in the renderer with Node integration enabled, achieving arbitrary code execution on the host system.