CVE-2026-40560

7.5 highEPSS 0.5%

High (7.5) in miyagawa starman. EPSS 0.5% chance of exploitation in the next 30 days.

Starman versions before 0.4018 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Starman 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.

Severity

CVSS 3.1

7.5 high

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

EPSS: 0.5% chance of exploitation in the next 30 days; higher than 41% of CVEs (scores of 2026-10-31)
CWE: CWE-444
Published: 2026-04-29
Modified: 2026-07-24
Record from: the NVD, synced 2026-10-19

Affected

miyagawa:starman

References

https://datatracker.ietf.org/doc/html/rfc7230#section-3.3.3
https://github.com/miyagawa/Starman/commit/ced205f0805027e9d9c0731f8c40b104220604ed.patch
https://metacpan.org/release/MIYAGAWA/Starman-0.4018/changes
http://www.openwall.com/lists/oss-security/2026/04/29/1

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