{"cve":"CVE-2026-40561","nvd":{"published":"2026-05-03T01:15:58.390","modified":"2026-10-26T20:10:00.160","status":"Modified","description":"Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence.\n\nStarlet 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.\n\nAn attacker could exploit this to smuggle malicious HTTP requests via a front-end reverse proxy.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-444"],"references":["https://datatracker.ietf.org/doc/html/rfc7230#section-3.3.3","https://github.com/kazuho/Starlet/commit/a7d5dfd1862aafa43e5eaca0fdb6acf4cc15b2d0.patch","https://metacpan.org/release/KAZUHO/Starlet-0.32/changes","http://www.openwall.com/lists/oss-security/2026/05/03/1"],"products":["kazuho:starlet"],"source":"nvd","synced_at":"2026-10-26T20:34:58.897451322+00:00"},"epss":{"cve":"CVE-2026-40561","score":0.00364,"percentile":0.2995,"date":"2026-10-26"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}