CVE-2026-73253
criticalMongoose is an embedded web server and network library.
Vendor / product: Cesanta — mongoose
Mongoose is an embedded web server and network library. Prior to version 7.22, an on-path network attacker with a wildcard certificate for a parent domain can impersonate deeper subdomains to a client using the built-in TLS stack. The mg_tls_verify_cert_san() and mg_tls_verify_cert_cn() functions in src/tls_builtin.c call mg_match(), whose wildcard can cross DNS label boundaries, so a pattern such as *.example.com can match foo.bar.example.com. The resulting hostname verification bypass permits interception and modification of TLS traffic. This issue is fixed in version 7.22.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Affected products
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
References
- https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71 security-advisories@github.com
- https://github.com/cesanta/mongoose/pull/3611 security-advisories@github.com
- https://github.com/cesanta/mongoose/releases/tag/7.22 security-advisories@github.com
- https://github.com/cesanta/mongoose/security/advisories/GHSA-jp6g-796f-39vp security-advisories@github.com
- https://github.com/cesanta/mongoose/security/advisories/GHSA-jp6g-796f-39vp 134c704f-9b21-4f2e-91b3-4a467353bcc0