Cyrus Imap
Monthly
Cyrus IMAP through 3.12.2 exposes mailbox ACL data to any authenticated user via the IMAP LISTRIGHTS command, which lacks the required admin-access authorization check. Any valid IMAP account holder can call LISTRIGHTS against arbitrary mailboxes they can name, learning which principals hold which access rights - data that should be restricted to mailbox administrators. No public exploit or active exploitation has been identified; vendor release notes reference 3.12.3 as the corrective release.
Cyrus IMAP through version 3.12.2 fails to invalidate URLAUTH-minted URLs when the authorizer's access is subsequently revoked, allowing continued unauthorized access to delegated mailbox content. The flaw (CWE-672: Operation on Resource after Expiration or Release) affects the URLAUTH extension defined in RFC 4467, which is designed to let users grant third-party access to mailbox data without sharing credentials. No public exploit code exists and this vulnerability is not listed in CISA KEV; real-world risk is highest in environments with active IMAP delegation workflows where access revocation is security-critical, such as departing employee scenarios.
Heap over-read in Cyrus IMAP through version 3.12.2 enables authenticated IMAP users to leak server heap memory by submitting a crafted email containing an RFC 822 MIME comment whose final character is a backslash. During message parsing, the server reads past the end of the message buffer into adjacent heap memory and returns the exposed content to the requesting user, resulting in partial, non-deterministic heap disclosure. No public exploit code or active exploitation (CISA KEV) has been identified at time of analysis; a fix is referenced in the Cyrus IMAP 3.12.3 release notes.
Cyrus IMAP through version 3.12.2 contains an authorization flaw in its XAPPLEPUSHSERVICE (XAPS) command that lets authenticated IMAP users enumerate arbitrary mailboxes belonging to other accounts and redirect Apple Push Notification Service alerts about those mailboxes to their own device. The flaw (CWE-863, Incorrect Authorization) does not expose message content - only whether a target mailbox exists and when its modification sequence (modseq) changes - but it enables cross-account probing and unauthorized push subscription in multi-tenant IMAP deployments. No public exploit code has been identified and this vulnerability is not listed in CISA KEV; the low CVSS score of 3.1 is consistent with the limited confidentiality impact and mandatory authentication requirement.
Incorrect authorization in Cyrus IMAP through 3.12.2 allows authenticated users to bypass mailbox ACL enforcement via the vacation Sieve script `:fcc` (file carbon copy) feature, enabling unauthorized message injection into any mailbox nameable by the script regardless of insert permissions. The CVSS vector (PR:L, AV:N) confirms network-triggerable exploitation requiring only a valid authenticated account, with low integrity and availability impact (C:N/I:L/A:L). No public exploit code and no CISA KEV listing exist at time of analysis; vendor-released patch version 3.12.3 addresses the flaw.
Cross-user information disclosure in Cyrus IMAP through 3.12.2 allows any authenticated IMAP user to enumerate folder names and retrieve message UIDs belonging to arbitrary other accounts via the ESEARCH command, creating a content oracle. The flaw (CWE-204, Observable Response Discrepancy) leaks mailbox structure - including folder names that may reveal sensitive organizational or personal context - without permitting reads of actual message content. No public exploit code has been identified at time of analysis, no CISA KEV listing exists, and the CVSS score of 4.3 reflects the authentication prerequisite and limited confidentiality impact, though risk is elevated in shared multi-tenant deployments such as ISPs and universities.
Unauthorized mailbox deletion in Cyrus IMAP through 3.12.2 allows any authenticated non-admin user to invoke the admin-only LOCALDELETE command, bypassing ACL enforcement entirely. Any user with a valid account on an affected server can permanently delete arbitrary mailboxes - including those they have no read, write, or administrative permissions over - simply by issuing the improperly guarded command. No public exploit has been identified at time of analysis, but the attack requires only authentication and knowledge of the command, making it low-complexity for any insider or account-compromised attacker.
URLAUTH token forgery in Cyrus IMAP through 3.12.2 allows a network-based unauthenticated attacker to read the contents of a victim's mailbox folder by computing a forged authentication token using a predictable HMAC-SHA1 key. The predictability arises specifically when a victim has never issued a URLAUTH-authenticated URL for a given folder, leaving the per-folder mboxkey absent and thus falling back to a computable value. No public exploit code has been identified and no active exploitation has been confirmed; real-world impact is further constrained by URLAUTH being an obscure IMAP extension with negligible public client adoption.
Unauthorized mailbox access in Cyrus IMAP through 3.12.2 allows any authenticated user to read email from mailboxes they have no ACL permissions on by exploiting the GENURLAUTH command's failure to enforce access controls before issuing URLAUTH tokens. The authorization boundary between mailboxes is effectively eliminated for any user who can name a target mailbox, undermining the server's entire multi-user isolation model. No public exploit has been identified at time of analysis and the vulnerability is not listed in CISA KEV, though the impact is materially more significant in multi-tenant or shared-server environments than the CVSS score of 3.5 suggests.
Cyrus IMAP before 3.8.3 and 3.10.x before 3.10.0-rc1 allows authenticated attackers to cause unbounded memory allocation by sending many LITERALs in a single command. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. This Allocation of Resources Without Limits vulnerability could allow attackers to exhaust system resources through uncontrolled allocation.
Cyrus IMAP before 3.0.3 allows remote authenticated users to write to arbitrary files via a crafted (1) SYNCAPPLY, (2) SYNCGET or (3) SYNCRESTORE command. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.
Cyrus IMAP through 3.12.2 exposes mailbox ACL data to any authenticated user via the IMAP LISTRIGHTS command, which lacks the required admin-access authorization check. Any valid IMAP account holder can call LISTRIGHTS against arbitrary mailboxes they can name, learning which principals hold which access rights - data that should be restricted to mailbox administrators. No public exploit or active exploitation has been identified; vendor release notes reference 3.12.3 as the corrective release.
Cyrus IMAP through version 3.12.2 fails to invalidate URLAUTH-minted URLs when the authorizer's access is subsequently revoked, allowing continued unauthorized access to delegated mailbox content. The flaw (CWE-672: Operation on Resource after Expiration or Release) affects the URLAUTH extension defined in RFC 4467, which is designed to let users grant third-party access to mailbox data without sharing credentials. No public exploit code exists and this vulnerability is not listed in CISA KEV; real-world risk is highest in environments with active IMAP delegation workflows where access revocation is security-critical, such as departing employee scenarios.
Heap over-read in Cyrus IMAP through version 3.12.2 enables authenticated IMAP users to leak server heap memory by submitting a crafted email containing an RFC 822 MIME comment whose final character is a backslash. During message parsing, the server reads past the end of the message buffer into adjacent heap memory and returns the exposed content to the requesting user, resulting in partial, non-deterministic heap disclosure. No public exploit code or active exploitation (CISA KEV) has been identified at time of analysis; a fix is referenced in the Cyrus IMAP 3.12.3 release notes.
Cyrus IMAP through version 3.12.2 contains an authorization flaw in its XAPPLEPUSHSERVICE (XAPS) command that lets authenticated IMAP users enumerate arbitrary mailboxes belonging to other accounts and redirect Apple Push Notification Service alerts about those mailboxes to their own device. The flaw (CWE-863, Incorrect Authorization) does not expose message content - only whether a target mailbox exists and when its modification sequence (modseq) changes - but it enables cross-account probing and unauthorized push subscription in multi-tenant IMAP deployments. No public exploit code has been identified and this vulnerability is not listed in CISA KEV; the low CVSS score of 3.1 is consistent with the limited confidentiality impact and mandatory authentication requirement.
Incorrect authorization in Cyrus IMAP through 3.12.2 allows authenticated users to bypass mailbox ACL enforcement via the vacation Sieve script `:fcc` (file carbon copy) feature, enabling unauthorized message injection into any mailbox nameable by the script regardless of insert permissions. The CVSS vector (PR:L, AV:N) confirms network-triggerable exploitation requiring only a valid authenticated account, with low integrity and availability impact (C:N/I:L/A:L). No public exploit code and no CISA KEV listing exist at time of analysis; vendor-released patch version 3.12.3 addresses the flaw.
Cross-user information disclosure in Cyrus IMAP through 3.12.2 allows any authenticated IMAP user to enumerate folder names and retrieve message UIDs belonging to arbitrary other accounts via the ESEARCH command, creating a content oracle. The flaw (CWE-204, Observable Response Discrepancy) leaks mailbox structure - including folder names that may reveal sensitive organizational or personal context - without permitting reads of actual message content. No public exploit code has been identified at time of analysis, no CISA KEV listing exists, and the CVSS score of 4.3 reflects the authentication prerequisite and limited confidentiality impact, though risk is elevated in shared multi-tenant deployments such as ISPs and universities.
Unauthorized mailbox deletion in Cyrus IMAP through 3.12.2 allows any authenticated non-admin user to invoke the admin-only LOCALDELETE command, bypassing ACL enforcement entirely. Any user with a valid account on an affected server can permanently delete arbitrary mailboxes - including those they have no read, write, or administrative permissions over - simply by issuing the improperly guarded command. No public exploit has been identified at time of analysis, but the attack requires only authentication and knowledge of the command, making it low-complexity for any insider or account-compromised attacker.
URLAUTH token forgery in Cyrus IMAP through 3.12.2 allows a network-based unauthenticated attacker to read the contents of a victim's mailbox folder by computing a forged authentication token using a predictable HMAC-SHA1 key. The predictability arises specifically when a victim has never issued a URLAUTH-authenticated URL for a given folder, leaving the per-folder mboxkey absent and thus falling back to a computable value. No public exploit code has been identified and no active exploitation has been confirmed; real-world impact is further constrained by URLAUTH being an obscure IMAP extension with negligible public client adoption.
Unauthorized mailbox access in Cyrus IMAP through 3.12.2 allows any authenticated user to read email from mailboxes they have no ACL permissions on by exploiting the GENURLAUTH command's failure to enforce access controls before issuing URLAUTH tokens. The authorization boundary between mailboxes is effectively eliminated for any user who can name a target mailbox, undermining the server's entire multi-user isolation model. No public exploit has been identified at time of analysis and the vulnerability is not listed in CISA KEV, though the impact is materially more significant in multi-tenant or shared-server environments than the CVSS score of 3.5 suggests.
Cyrus IMAP before 3.8.3 and 3.10.x before 3.10.0-rc1 allows authenticated attackers to cause unbounded memory allocation by sending many LITERALs in a single command. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. This Allocation of Resources Without Limits vulnerability could allow attackers to exhaust system resources through uncontrolled allocation.
Cyrus IMAP before 3.0.3 allows remote authenticated users to write to arbitrary files via a crafted (1) SYNCAPPLY, (2) SYNCGET or (3) SYNCRESTORE command. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.