CVE-2026-74234

medium

Description

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.

References

https://www.vulncheck.com/advisories/legora-2026-08-14-xss-via-mermaid-gray-matter-javascript-engine

https://legora.com/

Details

Source: Mitre, NVD

Published: 2026-08-17

Updated: 2026-08-17

Risk Information

CVSS v2

Base Score: 6.6

Vector: CVSS2#AV:N/AC:H/Au:S/C:C/I:C/A:N

Severity: Medium

CVSS v3

Base Score: 7.7

Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

Severity: High

CVSS v4

Base Score: 5.1

Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

Severity: Medium