XSS in B3log Siyuan
CVE-2026-23645
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.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (18.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 19th percentile — 18.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.000
Affected products
- B3log Siyuan — versions 3.5.4
- Siyuan-Note Siyuan — versions < 3.5.4-dev2
Weakness classification (CWE)
References
- github.com/siyuan-note/siyuan/security/advisories/GHSA-pcjq-j3mq-jv5j (Exploit, Patch, Vendor Advisory)
- github.com/siyuan-note/siyuan/issues/16844 (Patch, Issue Tracking)
- github.com/siyuan-note/siyuan/commit/11115da3d0de950593ee4ce375cf7f9018484388 (Patch)
Frequently asked questions
- What is CVE-2026-23645?
- CVE-2026-23645 is a medium-severity vulnerability in B3log Siyuan, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2026-01-16.
- How severe is CVE-2026-23645?
- Medium severity. CVSS v3 base score is 6.1 out of 10.