Heap-based Buffer Overflow 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.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applicationsSnyk Learn
Learn about Heap-based Buffer Overflow vulnerabilities in an interactive lesson.
Start learning- Snyk IDSNYK-UNMANAGED-CESANTAMONGOOSE-15874125
- published2 Apr 2026
- disclosed2 Apr 2026
- creditthe_evilsocket
Introduced: 2 Apr 2026
CVE-2026-5244 (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 Heap-based Buffer Overflow via the mg_tls_recv_cert function in the TLS 1.3 handler process. An attacker can execute arbitrary code or cause a denial of service by sending specially crafted data remotely to trigger a heap-based buffer overflow.