Authorization Bypass Through User-Controlled Key Affecting cesanta/mongoose package, versions [,7.21)
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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- published2 Apr 2026
- disclosed2 Apr 2026
- creditthe_evilsocket
Introduced: 2 Apr 2026
CVE-2026-5246 (opens in a new tab)How to fix?
Upgrade cesanta/mongoose to version 7.21 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 Authorization Bypass Through User-Controlled Key via the mg_tls_verify_cert_signature function. An attacker can gain unauthorized access by manipulating certificate signature verification remotely.
Note:
This is only exploitable if the attacker is able to craft or supply a malicious P-384 public key certificate.