Vulnerability Description
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.
CVSS Score
MEDIUM
Related Weaknesses (CWE)
References
- https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869
- https://github.com/cesanta/mongoose/pull/3611
- https://github.com/cesanta/mongoose/releases/tag/7.22
- https://github.com/cesanta/mongoose/security/advisories/GHSA-cc55-8v3r-59p8
- https://github.com/cesanta/mongoose/security/advisories/GHSA-cc55-8v3r-59p8
FAQ
What is CVE-2026-73258?
CVE-2026-73258 is a vulnerability with a CVSS score of 6.5 (MEDIUM). 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/h...
How severe is CVE-2026-73258?
CVE-2026-73258 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-73258?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.