XSS in Docmost
CVE-2026-23630
Docmost is open-source collaborative wiki and documentation software. In versions 0.3.0 through 0.23.2, Mermaid code block rendering is vulnerable to stored Cross-Site Scripting (XSS). The frontend can render attacker-controlled Mermaid diagrams using mermaid.render(), then inject the returned SVG/HTML into the DOM via dangerouslySetInnerHTML without sanitization. Mermaid per-diagram %%{init}%% directives allow overriding securityLevel and enabling htmlLabels, permitting arbitrary HTML/JS execution for any viewer. This issue has been fixed in version 0.24.0.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.003 (18.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 19th percentile — 18.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.000
Affected products
- Docmost — versions >= 0.3.0, < 0.24.0
Weakness classification (CWE)
References
- github.com/docmost/docmost/security/advisories/GHSA-r4hj-mc62-jmwj (Exploit, Vendor Advisory)
- github.com/docmost/docmost/commit/cb9f27da9a8b4940760e37e5238a1eb91e427daf (Patch)
- github.com/docmost/docmost/releases/tag/v0.24.0 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-23630?
- CVE-2026-23630 is a medium-severity vulnerability in Docmost, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-01-21.
- How severe is CVE-2026-23630?
- Medium severity. CVSS v3 base score is 5.4 out of 10.