{"id":"DEBIAN-CVE-2026-91991","details":"Tornado before 6.5.8 contains an incomplete fix for cookie attribute injection that allows attackers to inject arbitrary cookie attributes by passing capitalized or legacy keyword arguments to set_cookie. Attackers can embed semicolon-delimited data in capitalized parameters like Domain, Path, or SameSite to bypass validation and modify cookie security attributes.","modified":"2026-09-22T09:00:33.083989054Z","published":"2026-09-15T16:17:58.293Z","upstream":["CVE-2026-91991"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-91991"}],"affected":[{"package":{"name":"python-tornado","ecosystem":"Debian:12","purl":"pkg:deb/debian/python-tornado?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.2.0-3","6.2.0-3+deb12u1","6.2.0-3+deb12u2","6.2.0-3+deb12u3","6.2.0-3+deb12u4","6.3.2-1","6.4.0-1","6.4.0-2","6.4.1-1","6.4.1-2","6.4.1-3","6.4.2-1","6.4.2-2","6.4.2-3","6.5.2-1","6.5.2-2","6.5.2-3","6.5.4-0.1","6.5.4-1","6.5.5-1","6.5.5-2","6.5.5-3","6.5.5-4","6.5.5-5"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-91991.json"}},{"package":{"name":"python-tornado","ecosystem":"Debian:14","purl":"pkg:deb/debian/python-tornado?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.4.2-3","6.5.2-1","6.5.2-2","6.5.2-3","6.5.4-0.1","6.5.4-1","6.5.5-1","6.5.5-2","6.5.5-3","6.5.5-4","6.5.5-5"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-91991.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"}]}