Mongoose is an embedded web server and network library. Prior to 7.22, a remote attacker can send a crafted percent-encoded request path to a deployment using MG_ENABLE_DIRLIST and persuade a user to visit it. The mg_http_serve_dir() and listdir() path in src/http.c places the decoded request URI into the title and h1 elements without HTML entity encoding. The resulting reflected cross-site scripting executes in the Mongoose origin and can expose session data or perform actions as the victim. This issue is fixed in version 7.22.
Fix
Patch, vendor advisory and mitigation references on NVD 4
- https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71 Patch
- https://github.com/cesanta/mongoose/pull/3611 Issue Tracking, Patch
- https://github.com/cesanta/mongoose/security/advisories/GHSA-9cwm-487w-h25w Exploit, Vendor Advisory
- https://github.com/cesanta/mongoose/security/advisories/GHSA-9cwm-487w-h25w Exploit, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 5.4 · cesantaNVD modified 2026-10-18 20:10
Affected (CPE criteria) 1
cpe:2.3:a:cesanta:mongoose:*:*:*:*:*:*:*:*
References 5
- https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71 Patch
- https://github.com/cesanta/mongoose/pull/3611 Issue Tracking, Patch
- https://github.com/cesanta/mongoose/releases/tag/7.22 Release Notes
- https://github.com/cesanta/mongoose/security/advisories/GHSA-9cwm-487w-h25w Exploit, Vendor Advisory
- https://github.com/cesanta/mongoose/security/advisories/GHSA-9cwm-487w-h25w Exploit, Vendor Advisory