{"id":"UBUNTU-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":"2026-10-17T13:01:17.774040027Z","published":"2026-10-15T00:00:00Z","upstream":["CVE-2026-93483"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-93483"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-93483"},{"type":"REPORT","url":"https://www.znuny.org/en/advisories/zsa-2026-14"},{"type":"REPORT","url":"https://www.znuny.org/advisories"}],"affected":[{"package":{"name":"otrs2","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/otrs2?arch=source&distro=xenial"},"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"],"ecosystem_specific":{"binaries":[{"binary_name":"otrs","binary_version":"5.0.7-1"},{"binary_name":"otrs2","binary_version":"5.0.7-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93483.json"}},{"package":{"name":"otrs2","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/otrs2?arch=source&distro=bionic"},"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"],"ecosystem_specific":{"binaries":[{"binary_name":"otrs","binary_version":"6.0.5-1"},{"binary_version":"6.0.5-1","binary_name":"otrs2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93483.json"}},{"package":{"name":"otrs2","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/otrs2?arch=source&distro=focal"},"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"],"ecosystem_specific":{"binaries":[{"binary_name":"otrs","binary_version":"6.0.26-1"},{"binary_version":"6.0.26-1","binary_name":"otrs2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93483.json"}},{"package":{"name":"otrs2","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/otrs2?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.0.32-6","6.1.2-1","6.2.1-1","6.2.2-2"],"ecosystem_specific":{"binaries":[{"binary_name":"otrs2","binary_version":"6.2.2-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93483.json"}},{"package":{"name":"znuny","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/znuny?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.5.3-1","6.5.4-1","6.5.5-1","6.5.6-1"],"ecosystem_specific":{"binaries":[{"binary_version":"6.5.6-1","binary_name":"otrs2"},{"binary_name":"znuny","binary_version":"6.5.6-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93483.json"}},{"package":{"name":"znuny","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/znuny?arch=source&distro=stonking"},"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"],"ecosystem_specific":{"binaries":[{"binary_name":"otrs2","binary_version":"6.5.23-1"},{"binary_name":"znuny","binary_version":"6.5.23-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-93483.json"}},{"package":{"name":"znuny","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/znuny?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.5.15-2","6.5.18-1"],"ecosystem_specific":{"binaries":[{"binary_name":"otrs2","binary_version":"6.5.18-1"},{"binary_name":"znuny","binary_version":"6.5.18-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-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/AU:Y/R:U/RE:L/U:Red"},{"type":"Ubuntu","score":"medium"}]}