Mongoose is an embedded web server and network library. Prior to 7.23, a network attacker can impersonate a TLS server to a Mongoose client configured with a multi-certificate CA bundle. In src/tls_builtin.c, the mg_tls_init() function stores the bundle in tls->ca_bundle_der while tls->ca_der.len remains zero, and mg_tls_recv_cert() uses tls_bundle_find() to accept a Common Name match without calling mg_tls_verify_cert_signature(). A forged self-signed certificate can therefore satisfy hostname and CertificateVerify checks and enable interception, credential disclosure, traffic modification, and malicious responses. This issue is fixed in version 7.23.
Fix
Patch, vendor advisory and mitigation references on NVD 5
- https://github.com/cesanta/mongoose/commit/2988bc9df3a5efc9539471cb7455975fa25df483 Patch
- https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8 Vendor Advisory
- https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8 Vendor Advisory
- https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8 Vendor Advisory
- https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8 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 9.3 · cesantaNVD modified 2026-10-18 20:10
Affected (CPE criteria) 1
cpe:2.3:a:cesanta:mongoose:*:*:*:*:*:*:*:*
References 6
- https://github.com/cesanta/mongoose/commit/2988bc9df3a5efc9539471cb7455975fa25df483 Patch
- https://github.com/cesanta/mongoose/releases/tag/7.23 Release Notes
- https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8 Vendor Advisory
- https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8 Vendor Advisory
- https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8 Vendor Advisory
- https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8 Vendor Advisory