CVE-2026-31809 Scanner
CVE-2026-31809 Scanner - Cross-Site Scripting (XSS) vulnerability in SiYuan
Used 2.8k times · 5.9k assets checked · url
CVE
CVE-2026-31809
6.4
CVSSmedium
Exploitable remotely over the internet · no authentication required.
Description
SiYuan is a personal knowledge management system. Prior to 3.5.10, SiYuan's SVG sanitizer (SanitizeSVG) checks href attributes for the javascript: prefix using strings.HasPrefix(). However, inserting ASCII tab (	), newline ( ), or carriage return ( ) characters inside the javascript: string bypasses this prefix check. Browsers strip these characters per the WHATWG URL specification before parsing the URL scheme, so the JavaScript still executes. This allows an attacker to inject executable JavaScript into the unauthenticated /api/icon/getDynamicIcon endpoint, creating a reflected XSS. This is a second bypass of the fix for CVE-2026-29183 (fixed in v3.5.9). This vulnerability is fixed in 3.5.10.
Attack Vector
Network
Privileges Req.
None
User Interaction
P
siyuan
Updated Sep 18, 2026View on NVD →
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CVE history: siyuan
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