{"id":"DEBIAN-CVE-2026-16434","details":"Adminer 4.6.0 through 5.5.0 (fixed in 5.5.1) contains an incomplete fix for a prior X-Forwarded-Prefix vulnerability (GHSA-8478-xrj3-h9c2). The validation guard (bootstrap.inc.php) only rejects prefixes matching ^/[^/], blocking //evil.com but allowing values such as /\\evil.com whose second character is a backslash. Because browsers normalize backslash to forward slash, a network-path reference survives into REQUEST_URI and reaches cookie_path(), affecting the Set-Cookie Path attribute. Exploitation requires that clients can set the X-Forwarded-Prefix header (a misconfigured or absent reverse proxy). Impact is limited to anomalous cookie-path scoping.","modified":"2026-09-09T09:00:07.348770564Z","published":"2026-08-25T02:16:40.110Z","upstream":["CVE-2026-16434"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-16434"}],"affected":[{"package":{"name":"adminer","ecosystem":"Debian:12","purl":"pkg:deb/debian/adminer?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.8.1-1","4.8.1-2","4.8.1-4","5.1.0-1","5.2.1+dfsg-1","5.3.0+dfsg-1","5.4.0+dfsg-1","5.4.1+dfsg-1","5.4.2+dfsg-1","5.4.3+dfsg-1","5.4.4+dfsg-1","6.0.0-1","6.0.1-1","6.0.2-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-16434.json"}},{"package":{"name":"adminer","ecosystem":"Debian:13","purl":"pkg:deb/debian/adminer?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.2.1+dfsg-1","5.3.0+dfsg-1","5.4.0+dfsg-1","5.4.1+dfsg-1","5.4.2+dfsg-1","5.4.3+dfsg-1","5.4.4+dfsg-1","6.0.0-1","6.0.1-1","6.0.2-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-16434.json"}},{"package":{"name":"adminer","ecosystem":"Debian:14","purl":"pkg:deb/debian/adminer?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.0.0-1"}]}],"versions":["5.2.1+dfsg-1","5.3.0+dfsg-1","5.4.0+dfsg-1","5.4.1+dfsg-1","5.4.2+dfsg-1","5.4.3+dfsg-1","5.4.4+dfsg-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-16434.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/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"}]}