HTTP Request Smuggling 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.
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 applications- Snyk IDSNYK-UNMANAGED-CESANTAMONGOOSE-19233312
- published23 Aug 2026
- disclosed21 Aug 2026
- creditUnknown
Introduced: 21 Aug 2026
NewCVE-2026-73257 (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 HTTP Request Smuggling via the coexistence of both Content-Length and Transfer-Encoding headers in HTTP requests. An attacker can access or modify resources in another user context by exploiting desynchronization between the server and a reverse proxy.