CVE-2026-73257EPSS p50.4%
CVE-2026-73257CVE-2026-73257
cesanta / mongoose
Description
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.
Scoring
| CVSS | 9.1 () |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| EPSS | 0.67% probability of exploitation · percentile 50.4% · 2026-10-05T12:00:23Z |
| Last modified | 2026-09-29 |