{"id":"DEBIAN-CVE-2026-93483","details":"In Znuny through 7.3.6, an attacker can bypass specific standard login procedures and gain unauthorized access to sensitive system functions by manipulating a specific HTTP request header. Because the application incorrectly trusts this header, an attacker can impersonate any user, including administrators, without requiring a password. This grants full access to confidential data and system controls. More specifically, the HTTPBasicAuth modules for the agent (Kernel::System::Auth::HTTPBasicAuth) and customer (Kernel::System::CustomerAuth::HTTPBasicAuth) interfaces read the username to log in not only from $ENV{REMOTE_USER} (set by the web server after successful authentication), but also, as a fallback, from $ENV{HTTP_REMOTE_USER}, which is populated directly from an attacker-controllable \"Remote-User\" request header. On systems where HTTPBasicAuth was configured as the authentication backend, this allowed an attacker to log in as any existing user by sending a request with a forged Remote-User header, without providing any credentials.","modified":"2026-10-16T09:47:35.855035004Z","published":"2026-10-15T04:18:30.153Z","upstream":["CVE-2026-93483"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-93483"}],"affected":[{"package":{"name":"znuny","ecosystem":"Debian:12","purl":"pkg:deb/debian/znuny?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.3.2-3","6.3.3-1","6.3.3-1~bpo11+1","6.3.4-1","6.3.4-1~bpo11+1","6.4.2-1","6.4.2-1~bpo11+1","6.4.2-2","6.4.3-1","6.4.3-1~bpo11+1","6.4.4-1","6.4.5-1","6.4.5-1~bpo11+1","6.4.5-2","6.5.1-1","6.5.10-1","6.5.10-1~bpo12+1","6.5.11-1","6.5.11-1~bpo12+1","6.5.13-1","6.5.14-1","6.5.14-1~bpo12+1","6.5.15-1","6.5.15-2","6.5.15-2~bpo12+1","6.5.16-1","6.5.18-1","6.5.18-1~bpo13+1","6.5.19-1","6.5.20-1","6.5.21-1","6.5.22-1","6.5.22-1~bpo13+1","6.5.23-1","6.5.23-1~bpo13+1","6.5.24-1","6.5.24-1~bpo13+1","6.5.25-1","6.5.25-1~bpo13+1","6.5.26-1","6.5.3-1","6.5.3-1~bpo12+1","6.5.4-1","6.5.4-1~bpo12+1","6.5.5-1","6.5.5-1~bpo12+1","6.5.6-1","6.5.6-1~bpo12+1","6.5.8-1","6.5.8-1~bpo12+1","6.5.9-1","6.5.9-1~bpo12+1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-93483.json"}},{"package":{"name":"znuny","ecosystem":"Debian:13","purl":"pkg:deb/debian/znuny?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.3.2-3","6.3.3-1","6.3.3-1~bpo11+1","6.3.4-1","6.3.4-1~bpo11+1","6.4.2-1","6.4.2-1~bpo11+1","6.4.2-2","6.4.3-1","6.4.3-1~bpo11+1","6.4.4-1","6.4.5-1","6.4.5-1~bpo11+1","6.4.5-2","6.5.1-1","6.5.10-1","6.5.10-1~bpo12+1","6.5.11-1","6.5.11-1~bpo12+1","6.5.13-1","6.5.14-1","6.5.14-1~bpo12+1","6.5.15-1","6.5.15-2","6.5.15-2~bpo12+1","6.5.16-1","6.5.18-1","6.5.18-1~bpo13+1","6.5.19-1","6.5.20-1","6.5.21-1","6.5.22-1","6.5.22-1~bpo13+1","6.5.23-1","6.5.23-1~bpo13+1","6.5.24-1","6.5.24-1~bpo13+1","6.5.25-1","6.5.25-1~bpo13+1","6.5.26-1","6.5.3-1","6.5.3-1~bpo12+1","6.5.4-1","6.5.4-1~bpo12+1","6.5.5-1","6.5.5-1~bpo12+1","6.5.6-1","6.5.6-1~bpo12+1","6.5.8-1","6.5.8-1~bpo12+1","6.5.9-1","6.5.9-1~bpo12+1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-93483.json"}},{"package":{"name":"znuny","ecosystem":"Debian:14","purl":"pkg:deb/debian/znuny?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.5.25-1"}]}],"versions":["6.3.2-3","6.3.3-1","6.3.3-1~bpo11+1","6.3.4-1","6.3.4-1~bpo11+1","6.4.2-1","6.4.2-1~bpo11+1","6.4.2-2","6.4.3-1","6.4.3-1~bpo11+1","6.4.4-1","6.4.5-1","6.4.5-1~bpo11+1","6.4.5-2","6.5.1-1","6.5.10-1","6.5.10-1~bpo12+1","6.5.11-1","6.5.11-1~bpo12+1","6.5.13-1","6.5.14-1","6.5.14-1~bpo12+1","6.5.15-1","6.5.15-2","6.5.15-2~bpo12+1","6.5.16-1","6.5.18-1","6.5.18-1~bpo13+1","6.5.19-1","6.5.20-1","6.5.21-1","6.5.22-1","6.5.22-1~bpo13+1","6.5.23-1","6.5.23-1~bpo13+1","6.5.24-1","6.5.24-1~bpo13+1","6.5.25-1~bpo13+1","6.5.3-1","6.5.3-1~bpo12+1","6.5.4-1","6.5.4-1~bpo12+1","6.5.5-1","6.5.5-1~bpo12+1","6.5.6-1","6.5.6-1~bpo12+1","6.5.8-1","6.5.8-1~bpo12+1","6.5.9-1","6.5.9-1~bpo12+1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-93483.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L/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:Y/R:U/V:X/RE:L/U:Red"}]}