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OpenAdvisories
Medium · 6.3 CVE-2026-23630 EUVD-2026-4211

Docmost is vulnerable to stored Cross-Site Scripting (XSS) through Mermaid rendering

Published Jan 21, 2026 · Updated Jan 22, 2026 · Assigned by GitHub_M

Description

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.

Affected products

VendorProductAffectedFixed
docmost docmost >= 0.3.0, < 0.24.0 —

References