Bug 2538638

Summary: CVE-2026-73256 mongoose: Mongoose: HTTP/1.0 detection off-by-one enables request smuggling via chunked TE [fedora-all]
Product: [Fedora] Fedora Reporter: aedmond
Component: mongooseAssignee: Orphan Owner <extras-orphan>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: urgent Docs Contact:
Priority: urgent    
Version: rawhideCC: cz172638, extras-orphan, fedora
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["a551bddc-c1f9-47fa-959b-513f8ce89a80"]}
Fixed In Version: Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2520644    

Description aedmond 2026-09-22 19:49:00 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.