Improper Certificate Validation Affecting cesanta/mongoose package, versions [,7.22)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UNMANAGED-CESANTAMONGOOSE-19233307
- published23 Aug 2026
- disclosed21 Aug 2026
- creditUnknown
Introduced: 21 Aug 2026
NewCVE-2026-73253 (opens in a new tab)How to fix?
Upgrade cesanta/mongoose to version 7.22 or higher.
Overview
cesanta/mongoose is a networking library for C/C++. It implements event-driven non-blocking APIs for TCP, UDP, HTTP, WebSocket, MQTT.
Affected versions of this package are vulnerable to Improper Certificate Validation via the mg_match function used in certificate verification. An attacker can intercept and modify TLS traffic by presenting a wildcard certificate for a parent domain, which is incorrectly accepted for deeper subdomains due to improper wildcard matching.