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CVE-2026-40560                                       CPAN Security Group
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         CVE ID:  CVE-2026-40560
   Distribution:  Starman
       Versions:  before 0.4018

       MetaCPAN:  https://metacpan.org/dist/Starman
       VCS Repo:  https://github.com/miyagawa/Starman

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

Description
-----------
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.

Problem types
-------------
- CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP
   Request/Response Smuggling')

Solutions
---------
Upgrade to version 0.4018

References
----------
https://github.com/miyagawa/Starman/commit/ced205f0805027e9d9c0731f8c40b104220604ed.patch
https://metacpan.org/release/MIYAGAWA/Starman-0.4018/changes
https://datatracker.ietf.org/doc/html/rfc7230#section-3.3.3

Timeline
--------
- 2027-04-12: Issue identified by CPANSec
- 2027-04-27: Issue reported to software maintainer
- 2027-04-27: Fix committed to public Github repository
- 2027-04-27: Updated version uploaded to CPAN

Credits
-------
CPANSec, finder