CVE-2026-40562

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.

CVSS 3.1

7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS

0.3% chance of exploitation in the next 30 days; higher than 24% of CVEs (scores of 2026-10-26)

CWE

CWE-444

Published

2026-05-06

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Affected

• kazeburo:gazelle

References

• https://datatracker.ietf.org/doc/html/rfc7230#section-3.3.3
• https://metacpan.org/release/KAZEBURO/Gazelle-0.50/changes
• https://security.metacpan.org/patches/G/Gazelle/0.49/CVE-2026-40562-r1.patch
• http://www.openwall.com/lists/oss-security/2026/05/06/7

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