{"id":"CVE-2026-93483","aliases":["DEBIAN-CVE-2026-93483","EUVD-2026-101820","GHSA-g4fx-r8m5-c6r7","UBUNTU-CVE-2026-93483"],"status":"published","title":"In Znuny through 7.3.6, an attacker can bypass specific standard login procedures and gain...","description":"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.","severity":{"version":"4.0","score":9.5,"vector":"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/AU:Y/R:U/RE:L/U:Red","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00234,"percentile":0.14465,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-348"],"published":"2026-10-15T03:43:10Z","modified":"2026-10-28T17:46:31Z","fixes":[{"ecosystem":"Debian:14","package":"znuny","fixed_in":["6.5.25-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"znuny","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","6.5.26-1~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"]},{"source":"osv","ecosystem":"Debian:13","package":"znuny","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","6.5.26-1~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"]},{"source":"osv","ecosystem":"Debian:14","package":"znuny","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"]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"otrs2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.0.10-1","5.0.1-1","5.0.1-2","5.0.2-1","5.0.3-1","5.0.5-1","5.0.6-1","5.0.7-1"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"otrs2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.0.23-1","5.0.24-1","6.0.1-1","6.0.2-1","6.0.3-1","6.0.4-1","6.0.5-1"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"otrs2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.0.20-1","6.0.23-2","6.0.24-1","6.0.25-1","6.0.25-2","6.0.25-3","6.0.26-1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"otrs2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.0.32-6","6.1.2-1","6.2.1-1","6.2.2-2"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"znuny","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.5.3-1","6.5.4-1","6.5.5-1","6.5.6-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"znuny","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.5.18-1","6.5.20-1","6.5.21-1","6.5.22-1","6.5.23-1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"znuny","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.5.15-2","6.5.18-1"]}],"products":[{"vendor":"znuny","product":"znuny"}],"references":[{"url":"https://www.znuny.org/advisories","tags":["advisory","report"]},{"url":"https://www.znuny.org/en/advisories/zsa-2026-14","tags":["advisory","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-93483","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-g4fx-r8m5-c6r7"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93483.json","tags":["advisory"]},{"url":"https://github.com/znuny/znuny","tags":["package"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-93483","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-93483","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-93483","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-93483","description":"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.","status":"published","published":"2026-10-15T03:43:10.406Z","modified":"2026-10-19T18:42:25.087Z","cvss":[{"version":"4.0","score":9.5,"vector":"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/AU:Y/R:U/RE:L/U:Red","level":"critical","assessor":"cna"}],"cwes":["CWE-348"],"updated_at":"2026-11-02T14:19:54.50686Z"}],"euvd":[{"id":"EUVD-2026-101820","description":"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.","status":"published","published":"2026-10-15T03:43:10Z","modified":"2026-10-19T18:42:25Z","cvss":[{"version":"4.0","score":9.5,"vector":"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/AU:Y/R:U/RE:L/U:Red","level":"critical"}],"updated_at":"2026-11-02T16:59:49.097498Z"}],"ghsa":[{"id":"GHSA-g4fx-r8m5-c6r7","title":"In Znuny through 7.3.6, an attacker can bypass specific standard login procedures and gain...","description":"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.","status":"published","published":"2026-10-15T06:30:43Z","modified":"2026-10-15T06:30:51Z","cvss":[{"version":"4.0","score":9.5,"vector":"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","level":"critical"}],"cwes":["CWE-348"],"updated_at":"2026-11-02T15:13:35.252436Z"}],"nvd":[{"id":"CVE-2026-93483","description":"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.","status":"published","published":"2026-10-15T04:18:30.153Z","modified":"2026-10-19T19:18:14.38Z","cvss":[{"version":"4.0","score":9.5,"vector":"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","level":"critical","assessor":"secondary"}],"cwes":["CWE-348"],"updated_at":"2026-11-02T14:12:59.328869Z"}],"osv":[{"id":"CVE-2026-93483","description":"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.","status":"published","published":"2026-10-15T03:43:10.406Z","modified":"2026-10-28T02:31:09.037181779Z","cvss":[{"version":"4.0","score":9.5,"vector":"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/AU:Y/R:U/RE:L/U:Red","level":"critical"}],"cwes":["CWE-348"],"updated_at":"2026-11-02T15:45:20.931171Z"},{"id":"DEBIAN-CVE-2026-93483","description":"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.","status":"published","published":"2026-10-15T04:18:30.153Z","modified":"2026-10-23T18:05:05.3948368Z","cvss":[{"version":"4.0","score":9.5,"vector":"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","level":"critical"}],"updated_at":"2026-11-02T15:46:06.846102Z"},{"id":"UBUNTU-CVE-2026-93483","description":"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.","status":"published","published":"2026-10-15T04:18:00Z","modified":"2026-10-28T17:46:31Z","cvss":[{"version":"4.0","score":9.5,"vector":"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/AU:Y/R:U/RE:L/U:Red","level":"critical"}],"updated_at":"2026-11-02T16:57:44.071534Z"}]}}