BaselineWatch
Desk

CVE-2026-73256

9.1 critical SSVC exploitation: none Analyzed

Mongoose is an embedded web server and network library. Prior to 7.22, a remote unauthenticated attacker can exploit an HTTP/1.0 reverse-proxy deployment by sending a request with Transfer-Encoding: chunked and conflicting framing. The http_cb() function in src/http.c tests hm.proto.len with an impossible greater-than-eight condition even though mg_http_parse() requires an eight-byte protocol string, so is_http_1_0 is never set. Mongoose consequently processes chunked encoding that an HTTP/1.0 proxy can ignore, enabling request smuggling and unauthorized access or state changes. This issue is fixed in version 7.22.

Fix

Patch, vendor advisory and mitigation references on NVD 3

Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.

Change history 1

  1. First seenCVSS 9.1 · cesantaNVD modified 2026-10-18 20:10

Affected (CPE criteria) 1

  • cpe:2.3:a:cesanta:mongoose:*:*:*:*:*:*:*:*

References 4