CVE-2026-73253
Description
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.
How to fix
- cesanta mongoose7.22 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| cesanta mongoose | v < 7.22 | 7.22 |
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Attack Surface Management
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