CVE-2026-74234
HighCVSS 7.7Exploitation Probability (EPSS)
Low risk21th percentile - higher than 21% of all known CVEs
Summary
Legora before 2026-08-14 contains a cross-site scripting vulnerability that allows attackers to achieve arbitrary JavaScript execution in a victim's browser by embedding a Mermaid block prefixed with a gray-matter JavaScript front-matter directive, causing the front-matter parser to invoke eval() before any SVG sanitization occurs. Attackers can exploit this flaw through influenced Mermaid diagram content to execute arbitrary JavaScript in the user's browser context, with elevated impact on Word and Outlook add-in surfaces where bearer session tokens are persisted in localStorage.
Risk Assessment
The risk includes execution of malicious scripts in the user's browser context, which could lead to data theft, session hijacking, or attacks on office add-ins. Particularly dangerous is the storage of session tokens in localStorage.
Recommendation
It is recommended to upgrade Legora to a version after 2026-08-14. Also, avoid viewing untrusted Mermaid content and consider additional security measures such as CSP.
Original NVD description (English source)
Legora before 2026-08-14 contains a cross-site scripting vulnerability that allows attackers to achieve arbitrary JavaScript execution in a victim's browser by embedding a Mermaid block prefixed with a gray-matter JavaScript front-matter directive, causing the front-matter parser to invoke eval() before any SVG sanitization occurs. Attackers can exploit this flaw through influenced Mermaid diagram content to execute arbitrary JavaScript in the user's browser context, with elevated impact on Word and Outlook add-in surfaces where bearer session tokens are persisted in localStorage.