Open-Xchange Gmbh Ox Dovecot Pro vulnerabilities

CVE-2025-59032 [HIGH] CWE-20 CVE-2025-59032: ManageSieve AUTHENTICATE command crashes when using literal as SASL initial response. This can be us ManageSieve AUTHENTICATE command crashes when using literal as SASL initial response. This can be used to crash ManageSieve service repeatedly, making it unavailable for other users. Control access to ManageSieve port, or disable the service if it's not needed. Alternatively upgrade to a fixed version. No publicly available exploits are known.

CVE-2026-27858 [HIGH] CWE-400 CVE-2026-27858: Attacker can send a specifically crafted message before authentication that causes managesieve to al Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory. Attacker can force managesieve-login to be unavailable by repeatedly crashing the process. Protect access to managesieve protocol, or install fixed version. No publicly available exploits are known.

CVE-2026-24031 [HIGH] CWE-89 CVE-2026-24031: Dovecot SQL based authentication can be bypassed when auth_username_chars is cleared by admin. This Dovecot SQL based authentication can be bypassed when auth_username_chars is cleared by admin. This vulnerability allows bypassing authentication for any user and user enumeration. Do not clear auth_username_chars. If this is not possible, install latest fixed version. No publicly available exploits are known.

CVE-2026-27856 [HIGH] CWE-287 CVE-2026-27856: Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attac Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack. An attacker can use this to determine the configured credentials. Figuring out the credential will lead into full access to the affected component. Limit access to the doveadm http service port, install fixed version. No publicly available exploits a

CVE-2025-59031 [MEDIUM] CWE-200 CVE-2025-59031: Dovecot has provided a script to use for attachment to text conversion. This script unsafely handles Dovecot has provided a script to use for attachment to text conversion. This script unsafely handles zip-style attachments. Attacker can use specially crafted OOXML documents to cause unintended files on the system to be indexed and subsequently ending up in FTS indexes. Do not use the provided script, instead, use something else like FTS tika. No p

CVE-2025-59028 [MEDIUM] CWE-20 CVE-2025-59028: When sending invalid base64 SASL data, login process is disconnected from the auth server, causing a When sending invalid base64 SASL data, login process is disconnected from the auth server, causing all active authentication sessions to fail. Invalid BASE64 data can be used to DoS a vulnerable server to break concurrent logins. Install fixed version or disable concurrency in login processes (heavy perfomance penalty on large deployments). No public

CVE-2026-27857 [MEDIUM] CWE-400 CVE-2026-27857: Sending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage Sending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage. Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time periods by not sending the command ending LF. So attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB

CVE-2026-27855 [MEDIUM] CWE-294 CVE-2026-27855: Dovecot OTP authentication is vulnerable to replay attack under specific conditions. If auth cache i Dovecot OTP authentication is vulnerable to replay attack under specific conditions. If auth cache is enabled, and username is altered in passdb, then OTP credentials can be cached so that same OTP reply is valid. An attacker able to observe an OTP exchange is able to log in as the user. If authentication happens over unsecure connection, switch to

CVE-2026-27859 [MEDIUM] CWE-400 CVE-2026-27859: A mail message containing excessive amount of RFC 2231 MIME parameters causes LMTP to use too much C A mail message containing excessive amount of RFC 2231 MIME parameters causes LMTP to use too much CPU. A suitably formatted mail message causes mail delivery process to consume large amounts of CPU time. Use MTA capabilities to limit RFC 2231 MIME parameters in mail messages, or upgrade to fixed version where the processing is limited. No publicly

CVE-2026-0394 [MEDIUM] CWE-22 CVE-2026-0394: When dovecot has been configured to use per-domain passwd files, and they are placed one path compon When dovecot has been configured to use per-domain passwd files, and they are placed one path component above /etc, or slash has been added to allowed characters, path traversal can happen if the domain component is directory partial. This allows inadvertently reading /etc/passwd (or some other path which ends with passwd). If this file contains passwo

CVE-2026-27860 [LOW] CWE-90 CVE-2026-27860: If auth_username_chars is empty, it is possible to inject arbitrary LDAP filter to Dovecot's LDAP au If auth_username_chars is empty, it is possible to inject arbitrary LDAP filter to Dovecot's LDAP authentication. This leads to potentially bypassing restrictions and allows probing of LDAP structure. Do not clear out auth_username_chars, or install fixed version. No publicly available exploits are known.

CVE-2025-30189 [HIGH] CWE-1250 CVE-2025-30189: When cache is enabled, some passdb/userdb drivers incorrectly cache all users with same cache key, c When cache is enabled, some passdb/userdb drivers incorrectly cache all users with same cache key, causing wrong cached information to be used for these users. After cached login, all subsequent logins are for same user. Install fixed version or disable caching either globally or for the impacted passdb/userdb drivers. No publicly available exploits

CVE-2024-23185 [HIGH] CWE-770 CVE-2024-23185: Very large headers can cause resource exhaustion when parsing message. The message-parser normally r Very large headers can cause resource exhaustion when parsing message. The message-parser normally reads reasonably sized chunks of the message. However, when it feeds them to message-header-parser, it starts building up "full_value" buffer out of the smaller chunks. The full_value buffer has no size limit, so large headers can cause large memory usag

CVE-2024-23184 [MEDIUM] CWE-770 CVE-2024-23184: Having a large number of address headers (From, To, Cc, Bcc, etc.) becomes excessively CPU intensive Having a large number of address headers (From, To, Cc, Bcc, etc.) becomes excessively CPU intensive. With 100k header lines CPU usage is already 12 seconds, and in a production environment we observed 500k header lines taking 18 minutes to parse. Since this can be triggered by external actors sending emails to a victim, this is a security issue. An

CVE-2024-25584 [MEDIUM] CWE-345 CVE-2024-25584: Dovecot accepts dot LF DOT LF symbol as end of DATA command. RFC requires that it should always be C Dovecot accepts dot LF DOT LF symbol as end of DATA command. RFC requires that it should always be CR LF DOT CR LF. This causes Dovecot to convert single mail with LF DOT LF in middle, into two emails when relaying to SMTP. Dovecot will split mail with LF DOT LF into two mails. Upgrade to latest released version. No publicly available exploits are k