CVE-2026-73251Mongoose Built-in TLS: CA-bundle certificate chain accepted without any signature verification
Updated under an hour ago ()
Does this affect you?
It affects cesanta mongoose. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
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.
- CVSS
- 9.3 CRITICAL (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-295
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Analyzed
- Record last updated
- Aug 20, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
cesanta mongoose cesanta:mongoose (from the name) | before 7.23 | CNA record |
cesanta mongoose cesanta:mongoose | before 7.23 | NVD |
References
- https://github.com/cesanta/mongoose/security/advisories/GHSA-qj6j-2692-v2r8x-refsource-confirm, vendor-advisory
- https://github.com/cesanta/mongoose/commit/2988bc9df3a5efc9539471cb7455975fa25df483x-refsource-misc, patch
- https://github.com/cesanta/mongoose/releases/tag/7.23x-refsource-misc, release-notes
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.