Open Xchange Gmbh OX Dovecot Pro vulnerabilities, page 2
44 vulnerabilities
Known vulnerabilities in Open Xchange Gmbh OX Dovecot Pro, newest first, with CVSS severity, EPSS, KEV listings, ransomware use and the affected versions.
CVE-2026-52687alpinedovecot+4
EPSS score0.40%
An attacker that has valid credentials can select a compression algorithm for the IMAP connection whose decompression state requires a large amount of memory, and open several such connections. The memory limit of the process is reached with only a few connections, terminating the process and all connections it handles, which can cause degradation or denial of service for IMAP. Disable IMAP compression. Alternatively limit the number of connections handled by a single imap-login process, though this has a performance impact. Update to non-vulnerable version. No publicly available exploits are known.CVE-2026-42008debiandovecot+3EPSS score0.24%
Forwarding information received from a host listed as a trusted proxy is not kept separate from Dovecot's own authentication fields, so a value sent by that host can be injected as an internal authentication field. Any host permitted to act as a trusted proxy can authenticate as any user without knowing that user's password. This affects deployments whose password database honours a field that permits authentication without a password. Deployments that do not configure trusted proxies are not affected. Restrict the list of trusted proxy networks to hosts that are fully under your control. Update to non-vulnerable version. No publicly available exploits are known.CVE-2026-42395alpinedovecot+4EPSS score0.35%
A host listed as a trusted proxy can send forwarding information containing a NUL byte, which crashes the login process on the following login attempt. The login process is terminated, which can cause degradation or denial of service for logins. Deployments that do not configure trusted proxies are not affected. Restrict the list of trusted proxy networks to hosts that are fully under your control. Update to non-vulnerable version. No publicly available exploits are known.CVE-2026-42006alpinedovecot+15EPSS score0.82%
An attacker can cause uncontrolled memory usage with excessive bracing over IMAP. The fix in CVE-2026-27857 was incomplete, only blocking one way of doing this, so there was still another way left open. In particular, the fix was for closing braces, but you could still use open braces to bypass the limit. Using excessive bracing, attacker can cause memory usage up to configured memory limit. Install fixed version, or configure vsz_limit for imap process to low value. No publicly available exploits are known.CVE-2026-42007alpinedovecot+4EPSS score0.34%
An attacker that has valid credentials can use a Sieve script with the editheader extension to trigger a use-after-free in the mail editing code, and to write memory contents beyond the intended buffer into the delivered mail. This causes memory leak and opportunity to do memory corruption during mail delivery, which can crash the delivery process and may allow execution of arbitrary code in the context of that process. Disable the Sieve editheader extension. Update to non-vulnerable version. No publicly available exploits are known.CVE-2026-42393alpinedovecot+4EPSS score0.17%
The comparison used for the doveadm password and API key is not fully timing safe and can reveal the length of the configured secret. An attacker with access to the same network as the doveadm service, able to make repeated requests and measure response timing accurately, can learn the length of the secret, which reduces the effort needed to guess it. The secret value itself is not disclosed. Restrict network access to the doveadm service to trusted clients. Update to non-vulnerable version. No publicly available exploits are known.CVE-2026-42392alpinedovecot+4EPSS score0.27%
An attacker that has valid credentials can send an invalid IMAP URLFETCH command, which causes uninitialized memory to be included in the error response returned to the client. Process memory contents can be disclosed to the client, which may include sensitive data. Disable the IMAP URLAUTH functionality. Update to non-vulnerable version. No publicly available exploits are known.CVE-2026-42391alpinedovecot+4EPSS score0.45%
An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by the same process. This can cause degradation or denial of service for IMAP logins. Limit the number of connections handled by a single imap-login process. This has a performance impact though. Update to non-vulnerable version. No publicly available exploits are known.CVE-2026-0394debiandovecot+4EPSS score0.43%
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 passwords, it can be used to authenticate wrongly, or if this is userdb, it can unexpectly make system users appear valid users. Upgrade to fixed version, or use different authentication scheme that does not rely on paths. Alternatively you can also ensure that the per-domain passwd files are in some other location, such as /etc/dovecot/auth/%d. No publicly available exploits are known.CVE-2026-27858debiandovecot+4EPSS score1.04%
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-2026-27851alpinedovecot+5EPSS score0.57%
When safe filter is used with variable expansion, all following pipelines on the same string are incorrectly interpreted as safe too, enabling unsafe data to be unescaped. This can enable SQL / LDAP injection attacks when used in authentication. Avoid using safe filter until on fixed version. No publicly available exploits are known.CVE-2026-27856alpinedovecot+5EPSS score0.43%
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 are known.CVE-2026-27859alpinedovecot+5EPSS score0.40%
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 available exploits are known.CVE-2026-27852alpinedovecot+4EPSS score0.43%
An attacker that can send mail to a user can craft a message whose headers contain a very large number of email addresses or MIME parameters, which causes excessive memory usage when the message is later parsed. The message is still delivered, but reading it over IMAP can exhaust the memory limit of the process and terminate it, causing denial of service for the affected user. Update to non-vulnerable version. No publicly available exploits are known.CVE-2026-27855alpinedovecot+5EPSS score0.39%
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 SCRAM protocol. Alternatively ensure the communcations are secured, and if possible switch to OAUTH2 or SCRAM. No publicly available exploits are known.CVE-2026-27860alpinedovecot+5EPSS score0.34%
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-2026-27857alpinedovecot+5EPSS score0.80%
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 of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Install fixed version, there is no other remediation. No publicly available exploits are known.CVE-2026-24031alpinedovecot+5EPSS score0.40%
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-2026-33607alpinedovecot+4EPSS score0.55%
An attacker that has valid credentials can use IMAP LIST command to consume CPU. This can cause degradation or denial of service for IMAP. Monitor system for abnormal CPU usage and kill the offending process and lock account. Alternatively install fixed version. No publicly available exploits are known.CVE-2026-33603alpinedovecot+5EPSS score0.23%
Attacker can use a specially crafted base64 exchange between Dovecot and Client to fake SCRAM TLS channel binding. This requires that the attacker is able to position itself between Dovecot and the client connection. If successful, the attacker can eavesdrop communications between Dovecot and client as MITM proxy. Install fixed version. No publicly available exploits are known.