{"id":"CVE-2026-40561","state":"PUBLISHED","title":"Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence","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.","publishedAt":"2026-05-03T00:57:31.519Z","updatedAt":"2026-05-07T16:45:01.655Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","source":"CISA-ADP"},"assigner":"CPANSec","products":["KAZUHO Starlet"],"affected":[{"vendor":"KAZUHO","product":"Starlet","packageName":"Starlet","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"0.31","versionType":"custom"}],"collectionURL":"https://cpan.org/modules","programFiles":["lib/Starlet/Server.pm"],"programRoutines":[{"name":"Starlet::Server::handle_connection"}],"repo":"https://github.com/kazuho/Starlet"}],"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"],"weaknesses":["CWE-444"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/40xxx/CVE-2026-40561.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-40561","state":"PUBLISHED","datePublished":"2026-05-03T00:57:31.519Z","dateUpdated":"2026-05-07T16:45:01.655Z","assignerShortName":"CPANSec","assignerOrgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","dateReserved":"2026-04-14T11:35:53.644Z"},"containers":{"cna":{"title":"Starlet versions through 0.31 for Perl allows HTTP Request Smuggling via Improper Header Precedence","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"KAZUHO","product":"Starlet","packageName":"Starlet","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"0.31","versionType":"custom"}],"collectionURL":"https://cpan.org/modules","programFiles":["lib/Starlet/Server.pm"],"programRoutines":[{"name":"Starlet::Server::handle_connection"}],"repo":"https://github.com/kazuho/Starlet"}],"references":[{"url":"https://datatracker.ietf.org/doc/html/rfc7230#section-3.3.3"},{"url":"https://github.com/kazuho/Starlet/commit/a7d5dfd1862aafa43e5eaca0fdb6acf4cc15b2d0.patch","tags":["patch"]},{"url":"https://metacpan.org/release/KAZUHO/Starlet-0.32/changes","tags":["release-notes"]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-444","description":"CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"CPANSec","orgId":"9b29abf9-4ab0-4765-b253-1875cd9b441e","dateUpdated":"2026-05-07T16:45:01.655Z"},"credits":[{"lang":"en","type":"finder","value":"CPANSec"}],"impacts":[{"capecId":"CAPEC-33","descriptions":[{"lang":"en","value":"CAPEC-33 HTTP Request Smuggling"}]}],"solutions":[{"lang":"en","value":"Upgrade to Starlet 0.32 or later."}],"source":{"discovery":"UNKNOWN"},"timeline":[{"lang":"en","time":"2019-11-19T00:00:00.000Z","value":"Patch submitted to Starlet 0.31"},{"lang":"en","time":"2026-04-12T00:00:00.000Z","value":"Issue identified by CPANSec"},{"lang":"en","time":"2026-04-28T00:00:00.000Z","value":"Maintainer notified"},{"lang":"en","time":"2026-05-02T00:00:00.000Z","value":"Determined that the issue was already public on GitHub"},{"lang":"en","time":"2026-05-06T00:00:00.000Z","value":"Starlet 0.32 released with a fix"}],"workarounds":[{"lang":"en","value":"Migrate to Starman 0.4018 or later which has fixed this issue or apply the patch."}],"x_generator":{"engine":"cpansec-cna-tool 0.1"}},"adp":[{"title":"CVE Program Container","references":[{"url":"http://www.openwall.com/lists/oss-security/2026/05/03/1"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2026-05-03T03:04:55.098Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":5.3,"attackVector":"NETWORK","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","integrityImpact":"LOW","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"NONE","privilegesRequired":"NONE","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-05-04T13:54:42.679845Z","id":"CVE-2026-40561","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-04T13:54:47.941Z"}}]}}}