CVE-2026-73251

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.

• CWE-295

• https://github.com/cesanta/mongoose/commit/2988bc9df3a5efc9539471cb7455975fa25df483
• https://github.com/cesanta/mongoose/releases/tag/7.23
• https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8
• https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8
• https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8
• https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8

Published

Aug 20, 2026

Last Modified

Sep 9, 2026

Status

Awaiting Analysis

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
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