CPANSA-Starlet-2026-40561: Starlet vulnerability
| Publisher | giterlizzi | Document category | csaf_security_advisory |
|---|---|---|---|
| Initial release date | 2026-05-03T00:00:00 | Engine | CSAF Perl Toolkit 0.26 |
| Current release date | 2026-05-03T00:00:00 | Build Date | |
| Current version | 1 | Status | final |
| CVSS v3.1 Base Score | 5.3 | Severity | |
| Original language | Language | en | |
| Also referred to | |||
Vulnerability Description
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.
Vulnerabilities
CVE-2026-40561
Vulnerability DescriptionStarlet 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.
| Weakness | CWE-444 : Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') |
|---|
Product status
Known affected
| Product | Score | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Starlet less than 0.32 |
|
Fixed
- Starlet greater than or equal 0.32
giterlizzi
Namespace: https://github.com/giterlizzi/
gdt@cpan.org
References
- CPANSA-Starlet-2026-40561 JSON self
https://raw.githubusercontent.com/giterlizzi/perl-CPANSA-CSAF/develop/csaf/white/2026/cpansa-starlet-2026-40561.json - https://datatracker.ietf.org/doc/html/rfc7230#section-3.3.3 external
https://datatracker.ietf.org/doc/html/rfc7230#section-3.3.3 - https://github.com/kazuho/Starlet/commit/a7d5dfd1862aafa43e5eaca0fdb6acf4cc15b2d0.patch external
https://github.com/kazuho/Starlet/commit/a7d5dfd1862aafa43e5eaca0fdb6acf4cc15b2d0.patch - https://metacpan.org/release/KAZUHO/Starlet-0.32/changes external
https://metacpan.org/release/KAZUHO/Starlet-0.32/changes - http://www.openwall.com/lists/oss-security/2026/05/03/1 external
http://www.openwall.com/lists/oss-security/2026/05/03/1 - CVE-2026-40561 (NVD) external
https://nvd.nist.gov/vuln/detail/CVE-2026-40561
Revision history
| Version | Date of the revision | Summary of the revision |
|---|---|---|
| 1 | Sun May 3 00:00:00 2026 | First release |
Sharing rules
TLP:WHITE
For the TLP version see: https://www.first.org/tlp/