CVE-2026-73257 — Mongoose: Content-Length + Transfer-Encoding coexistence enables request smuggling
Mongoose is an embedded web server and network library. Priro to version 7.22, a remote unauthenticated attacker can send an HTTP request containing both Content-Length and Tran…
Published: 2026-08-20 · CVSS: 9.1 · CVSS 3.1
Mongoose is an embedded web server and network library. Priro to version 7.22, a remote unauthenticated attacker can send an HTTP request containing both Content-Length and Transfer-Encoding: chunked. The cl_count and te_count checks in the mg_http_parse() and http_cb() paths in src/http.c accept both headers and prioritize chunked encoding, while a Content-Length-preferring reverse proxy can use a different request boundary. This CL.TE desynchronization can inject requests that access or modify resources in another user context. This issue is fixed in version 7.22.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7