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.
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Test your applications- Snyk IDSNYK-UNMANAGED-CESANTAMONGOOSE-19233305
- published23 Aug 2026
- disclosed21 Aug 2026
- creditUnknown
Introduced: 21 Aug 2026
NewCVE-2026-73256 (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 http_cb function. An attacker can gain unauthorized access or perform state changes by sending specially crafted HTTP requests with conflicting Transfer-Encoding: chunked headers through an HTTP/1.0 reverse proxy.