{"id":"UBUNTU-CVE-2026-47085","details":"An issue was discovered in cyrus-imapd in Cyrus IMAP through 3.12.2. URLAUTH token forgery can occur via a missing mboxkey. If an attacker knew a folder name on the victim's account for which the victim had never issued an auth URL, they could forge a working URLAUTH token by computing an HMAC-SHA1 value with a predictable key, giving them read access to the mailbox. (URLAUTH is an obscure feature, meaning that the odds of any user actually being susceptible to this attack are very low. Perhaps no public clients use URLAUTH.)","modified":"2026-07-29T07:58:05Z","published":"2026-07-16T19:16:00Z","upstream":["CVE-2026-47085"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-47085"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-47085"},{"type":"REPORT","url":"https://www.cyrusimap.org/3.12/imap/download/release-notes/3.12/x/3.12.3.html"},{"type":"REPORT","url":"https://www.cyrusimap.org/imap/download/release-notes/index.html"}],"affected":[{"package":{"name":"cyrus-imapd","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/cyrus-imapd?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.5.10-3build1","2.5.10-3build2","2.5.10-3ubuntu1","2.5.10-3ubuntu1.1","2.5.10-3ubuntu1.1+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"cyrus-admin","binary_version":"2.5.10-3ubuntu1.1+esm1"},{"binary_name":"cyrus-caldav","binary_version":"2.5.10-3ubuntu1.1+esm1"},{"binary_name":"cyrus-clients","binary_version":"2.5.10-3ubuntu1.1+esm1"},{"binary_version":"2.5.10-3ubuntu1.1+esm1","binary_name":"cyrus-common"},{"binary_name":"cyrus-imapd","binary_version":"2.5.10-3ubuntu1.1+esm1"},{"binary_name":"cyrus-murder","binary_version":"2.5.10-3ubuntu1.1+esm1"},{"binary_version":"2.5.10-3ubuntu1.1+esm1","binary_name":"cyrus-nntpd"},{"binary_name":"cyrus-pop3d","binary_version":"2.5.10-3ubuntu1.1+esm1"},{"binary_version":"2.5.10-3ubuntu1.1+esm1","binary_name":"cyrus-replication"},{"binary_name":"libcyrus-imap-perl","binary_version":"2.5.10-3ubuntu1.1+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47085.json"}},{"package":{"name":"cyrus-imapd","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/cyrus-imapd?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.0.11-1","3.0.11-1build1","3.0.12-1","3.0.12-2","3.0.12-2ubuntu2","3.0.12-2ubuntu3","3.0.13-2ubuntu1","3.0.13-3ubuntu1","3.0.13-4ubuntu1","3.0.13-5","3.0.13-5ubuntu0.1~esm1","3.0.13-5ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_version":"3.0.13-5ubuntu0.1~esm2","binary_name":"cyrus-admin"},{"binary_name":"cyrus-caldav","binary_version":"3.0.13-5ubuntu0.1~esm2"},{"binary_name":"cyrus-clients","binary_version":"3.0.13-5ubuntu0.1~esm2"},{"binary_name":"cyrus-common","binary_version":"3.0.13-5ubuntu0.1~esm2"},{"binary_name":"cyrus-imapd","binary_version":"3.0.13-5ubuntu0.1~esm2"},{"binary_version":"3.0.13-5ubuntu0.1~esm2","binary_name":"cyrus-murder"},{"binary_name":"cyrus-nntpd","binary_version":"3.0.13-5ubuntu0.1~esm2"},{"binary_version":"3.0.13-5ubuntu0.1~esm2","binary_name":"cyrus-pop3d"},{"binary_name":"cyrus-replication","binary_version":"3.0.13-5ubuntu0.1~esm2"},{"binary_name":"libcyrus-imap-perl","binary_version":"3.0.13-5ubuntu0.1~esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47085.json"}},{"package":{"name":"cyrus-imapd","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/cyrus-imapd?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.2.6-2build1","3.4.2-2","3.4.2-2build1","3.4.3-2","3.4.3-3","3.4.3-3build2","3.4.3-3ubuntu0.1","3.4.3-3ubuntu0.1+esm1","3.4.3-3ubuntu0.3","3.4.3-3ubuntu0.3+esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"3.4.3-3ubuntu0.3+esm1","binary_name":"cyrus-admin"},{"binary_name":"cyrus-caldav","binary_version":"3.4.3-3ubuntu0.3+esm1"},{"binary_name":"cyrus-clients","binary_version":"3.4.3-3ubuntu0.3+esm1"},{"binary_name":"cyrus-common","binary_version":"3.4.3-3ubuntu0.3+esm1"},{"binary_name":"cyrus-imapd","binary_version":"3.4.3-3ubuntu0.3+esm1"},{"binary_name":"cyrus-murder","binary_version":"3.4.3-3ubuntu0.3+esm1"},{"binary_name":"cyrus-nntpd","binary_version":"3.4.3-3ubuntu0.3+esm1"},{"binary_name":"cyrus-pop3d","binary_version":"3.4.3-3ubuntu0.3+esm1"},{"binary_version":"3.4.3-3ubuntu0.3+esm1","binary_name":"cyrus-replication"},{"binary_name":"libcyrus-imap-perl","binary_version":"3.4.3-3ubuntu0.3+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-47085.json"}},{"package":{"name":"cyrus-imapd","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/cyrus-imapd?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.8.0-5","3.8.1-1","3.8.1-1build1","3.8.1-1build2","3.8.1-3","3.8.1-3build3","3.8.2-1","3.8.2-1ubuntu0.1~esm1","3.8.2-1ubuntu0.2","3.8.2-1ubuntu0.2+esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"3.8.2-1ubuntu0.2+esm1","binary_name":"cyrus-admin"},{"binary_name":"cyrus-caldav","binary_version":"3.8.2-1ubuntu0.2+esm1"},{"binary_name":"cyrus-clients","binary_version":"3.8.2-1ubuntu0.2+esm1"},{"binary_version":"3.8.2-1ubuntu0.2+esm1","binary_name":"cyrus-common"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