What’s Vulnerable › Vulnerabilities

CVE-2026-23630: Docmost is vulnerable to stored Cross-Site Scripting (XSS) through Mermaid rendering

• Severity: medium (CVSS 5.4 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: 2026-01-21 · updated 2026-06-17
• Weakness: CWE-79

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

• docmost: from 0.3.0 before 0.24.0 — fixed in 0.24.0

How to fix

Upgrade to a fixed version: docmost 0.24.0. Check the vendor advisory for mitigations.

References

• https://github.com/docmost/docmost/commit/cb9f27da9a8b4940760e37e5238a1eb91e427daf
• https://github.com/docmost/docmost/releases/tag/v0.24.0
• https://github.com/docmost/docmost/security/advisories/GHSA-r4hj-mc62-jmwj

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