CVE-2026-31807 PUBLISHED

SiYuan has a SVG Sanitizer Bypass via `<animate>` Element — Unauthenticated XSS

Assigner: GitHub_M
Reserved: 09.03.2026 Published: 10.03.2026 Updated: 10.03.2026

SiYuan is a personal knowledge management system. Prior to 3.5.10, SiYuan's SVG sanitizer (SanitizeSVG) blocks dangerous elements (<script>, <iframe>, <foreignobject>) and removes on* event handlers and javascript: in href attributes. However, it does NOT block SVG animation elements (<animate>, <set>) which can dynamically set attributes to dangerous values at runtime, bypassing the static sanitization. This allows an attacker to inject executable JavaScript into the unauthenticated /api/icon/getDynamicIcon endpoint (type=8), creating a reflected XSS. This is a bypass of the fix for CVE-2026-29183 (fixed in v3.5.9). This vulnerability is fixed in v3.5.10.

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
CVSS Score: 6.4

Product Status

Vendor siyuan-note
Product siyuan
Versions
  • Version < 3.5.10 is affected

References

Problem Types

  • CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CWE