Threats affecting pkg:github/Starman

CVE-2026-40560 is a high-severity vulnerability in MIYAGAWA Starman versions before 0.4018 for Perl. The issue arises because Starman incorrectly prioritizes the Content-Length header over the Transfer-Encoding: chunked header when both are present in an HTTP request, contrary to RFC 7230 section 3.3.3. This improper header precedence enables HTTP Request Smuggling attacks, where an attacker can send crafted requests that are interpreted inconsistently by front-end reverse proxies and the backend server. No official patch or remediation guidance is currently available from the vendor. There are no known exploits in the wild at this time. The vulnerability affects network-exposed services and has a CVSS score of 7.5, indicating high severity.