medium5.3
CVE-2026-40561
Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence.
Impact
Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence. Starlet 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
| Vendor | Product | Affected versions |
|---|---|---|
| Kazuho | Starlet | through 0.31 |