Description
Gazelle versions through 0.49 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Gazelle incorrectly prioritizes "Content-Length" over "Transfer-Encoding: chunked" when both headers are present in an HTTP request. Per RFC 7230 3.3.3, Transfer-Encoding must take precedence. An attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.
Affected products
kazeburo: gazelle
References4
- security.metacpan.org/patches/G/Gazelle/0.49/CVE-2026-40562-r1.… Patch
- datatracker.ietf.org/doc/html/rfc7230#section-3.3.3 Third Party Advisory
- metacpan.org/release/KAZEBURO/Gazelle-0.50/changes Release Notes
- www.openwall.com/lists/oss-security/2026/05/06/7 Mailing ListThird Party Advisory
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - EPSS — exploit probability
- 0% percentile: 25 · as of 13 November 2026
- CWE
- CWE-444
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.