CVE-2026-31807

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

Published Mar 10, 2026 CVSS 4.0 · 6.4 Medium EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-5hc8-qmg8-pw27 SiYuan has a SVG Sanitizer Bypass via `<animate>` Element — Unauthenticated XSS
History
Type Values Removed Values Added
First Time appeared B3log
B3log siyuan
CPEs cpe:2.3:a:b3log:siyuan:*:*:*:*:*:*:*:*
Vendors & Products B3log
B3log siyuan
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Siyuan
Siyuan siyuan
Vendors & Products Siyuan
Siyuan siyuan
Type Values Removed Values Added
Description 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.
Title SiYuan has a SVG Sanitizer Bypass via `<animate>` Element — Unauthenticated XSS
Weaknesses CWE-79
References
Metrics cvssV4_0

{'score': 6.4, '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Mar 11, 2026, 4:00 PM
Reserved
Mar 9, 2026, 4:33 PM
Status
Analyzed
Published
Mar 10, 2026, 9:16 PM
Modified
Jun 17, 2026, 10:34 AM