{"id":"UBUNTU-CVE-2026-40561","details":"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.","modified":"2026-05-20T16:25:40.802164973Z","published":"2026-05-03T01:15:00Z","upstream":["CVE-2026-40561"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-40561"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-40561"},{"type":"REPORT","url":"https://lists.security.metacpan.org/cve-announce/msg/39593408/"}],"affected":[{"package":{"name":"starlet","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/starlet?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.25-1","0.26-1","0.28-1"],"ecosystem_specific":{"binaries":[{"binary_name":"starlet","binary_version":"0.28-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40561.json"}},{"package":{"name":"starlet","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/starlet?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.31-1"],"ecosystem_specific":{"binaries":[{"binary_version":"0.31-1","binary_name":"starlet"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40561.json"}},{"package":{"name":"starlet","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/starlet?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.31-1"],"ecosystem_specific":{"binaries":[{"binary_name":"starlet","binary_version":"0.31-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40561.json"}},{"package":{"name":"starlet","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/starlet?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.31-1.1"],"ecosystem_specific":{"binaries":[{"binary_name":"starlet","binary_version":"0.31-1.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40561.json"}},{"package":{"name":"starlet","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/starlet?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.31-2"],"ecosystem_specific":{"binaries":[{"binary_name":"starlet","binary_version":"0.31-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40561.json"}},{"package":{"name":"starlet","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/starlet?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.31-2"],"ecosystem_specific":{"binaries":[{"binary_name":"starlet","binary_version":"0.31-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40561.json"}},{"package":{"name":"starlet","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/starlet?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.31-2","0.31-2build1"],"ecosystem_specific":{"binaries":[{"binary_name":"starlet","binary_version":"0.31-2build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40561.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},{"type":"Ubuntu","score":"medium"}]}