What’s Vulnerable › Vulnerabilities

CVE-2026-23645: SiYuan Vulnerable to Stored Cross-Site Scripting (XSS) via Unrestricted SVG File Upload

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-01-16 · updated 2026-06-17
• Weakness: CWE-79

Description

SiYuan is self-hosted, open source personal knowledge management software. Prior to 3.5.4-dev2, a Stored Cross-Site Scripting (XSS) vulnerability exists in SiYuan Note. The application does not sanitize uploaded SVG files. If a user uploads and views a malicious SVG file (e.g., imported from an untrusted source), arbitrary JavaScript code is executed in the context of their authenticated session. This vulnerability is fixed in 3.5.4-dev2.

Affected products

• siyuan-note siyuan: before 3.5.4; 3.5.4-dev1 — fixed in 3.5.4

How to fix

Upgrade to a fixed version: siyuan-note siyuan 3.5.4. Check the vendor advisory for mitigations.

References

• https://github.com/siyuan-note/siyuan/commit/11115da3d0de950593ee4ce375cf7f9018484388
• https://github.com/siyuan-note/siyuan/issues/16844
• https://github.com/siyuan-note/siyuan/security/advisories/GHSA-pcjq-j3mq-jv5j

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