Mongoose is an embedded web server and network library. Prior to 7.22, a remote attacker can place a lone carriage return or line feed in multipart input processed by mg_http_next_multipart() in src/http.c. The loops comparing s[b] and s[b + 1], and s[h2] and s[h2 + 1], use an incorrect AND condition and stop when either character resembles part of a CRLF terminator. This truncates headers, filenames, or boundaries and can cause an application to accept dangerous content after seeing a misleading Content-Type value. 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-cc55-8v3r-59p8 Exploit, Vendor Advisory
- https://github.com/cesanta/mongoose/security/advisories/GHSA-cc55-8v3r-59p8 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 6.5 · 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-cc55-8v3r-59p8 Exploit, Vendor Advisory
- https://github.com/cesanta/mongoose/security/advisories/GHSA-cc55-8v3r-59p8 Exploit, Vendor Advisory