Vulnerability Details CVE-2026-73253
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.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.004
EPSS Ranking 26.7%
CVSS Severity
CVSS v3 Score 9.1
References
- https://github.com/cesanta/mongoose/commit/a9df523f76f43a38bd53b4232b9cfd4c16869e71
- https://github.com/cesanta/mongoose/pull/3611
- https://github.com/cesanta/mongoose/releases/tag/7.22
- https://github.com/cesanta/mongoose/security/advisories/GHSA-jp6g-796f-39vp
- https://github.com/cesanta/mongoose/security/advisories/GHSA-jp6g-796f-39vp
Products affected by CVE-2026-73253
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cpe:2.3:a:cesanta:mongoose:-
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cpe:2.3:a:cesanta:mongoose:3.2
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cpe:2.3:a:cesanta:mongoose:3.3
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cpe:2.3:a:cesanta:mongoose:3.4
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cpe:2.3:a:cesanta:mongoose:3.5
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cpe:2.3:a:cesanta:mongoose:3.6
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cpe:2.3:a:cesanta:mongoose:3.7
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cpe:2.3:a:cesanta:mongoose:3.8
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cpe:2.3:a:cesanta:mongoose:4.0
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cpe:2.3:a:cesanta:mongoose:4.1
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cpe:2.3:a:cesanta:mongoose:5.0
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cpe:2.3:a:cesanta:mongoose:5.1
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cpe:2.3:a:cesanta:mongoose:5.2
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cpe:2.3:a:cesanta:mongoose:5.3
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cpe:2.3:a:cesanta:mongoose:5.4
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cpe:2.3:a:cesanta:mongoose:5.5
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cpe:2.3:a:cesanta:mongoose:5.6
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cpe:2.3:a:cesanta:mongoose:6.0
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cpe:2.3:a:cesanta:mongoose:6.1
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cpe:2.3:a:cesanta:mongoose:6.10
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cpe:2.3:a:cesanta:mongoose:6.11
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cpe:2.3:a:cesanta:mongoose:6.12
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cpe:2.3:a:cesanta:mongoose:6.13
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cpe:2.3:a:cesanta:mongoose:6.14
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cpe:2.3:a:cesanta:mongoose:6.15
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cpe:2.3:a:cesanta:mongoose:6.16
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cpe:2.3:a:cesanta:mongoose:6.17
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cpe:2.3:a:cesanta:mongoose:6.18
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cpe:2.3:a:cesanta:mongoose:6.2
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cpe:2.3:a:cesanta:mongoose:6.3
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cpe:2.3:a:cesanta:mongoose:6.4
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cpe:2.3:a:cesanta:mongoose:6.5
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cpe:2.3:a:cesanta:mongoose:6.6
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cpe:2.3:a:cesanta:mongoose:6.7
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cpe:2.3:a:cesanta:mongoose:6.8
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cpe:2.3:a:cesanta:mongoose:6.9
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cpe:2.3:a:cesanta:mongoose:7.0
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cpe:2.3:a:cesanta:mongoose:7.1
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cpe:2.3:a:cesanta:mongoose:7.10
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cpe:2.3:a:cesanta:mongoose:7.11
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cpe:2.3:a:cesanta:mongoose:7.12
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cpe:2.3:a:cesanta:mongoose:7.13
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cpe:2.3:a:cesanta:mongoose:7.14
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cpe:2.3:a:cesanta:mongoose:7.15
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cpe:2.3:a:cesanta:mongoose:7.16
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cpe:2.3:a:cesanta:mongoose:7.17
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cpe:2.3:a:cesanta:mongoose:7.18
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cpe:2.3:a:cesanta:mongoose:7.19
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cpe:2.3:a:cesanta:mongoose:7.2
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cpe:2.3:a:cesanta:mongoose:7.20
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cpe:2.3:a:cesanta:mongoose:7.21
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cpe:2.3:a:cesanta:mongoose:7.3
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cpe:2.3:a:cesanta:mongoose:7.4
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cpe:2.3:a:cesanta:mongoose:7.5
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cpe:2.3:a:cesanta:mongoose:7.6
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cpe:2.3:a:cesanta:mongoose:7.7
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cpe:2.3:a:cesanta:mongoose:7.8
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cpe:2.3:a:cesanta:mongoose:7.9