Dovecot 関連製品全体の CVE とセキュリティ脆弱性情報を集約し、CVSS、EPSS、公開日、脆弱性情報データを掲載しています。
過去の問題は主に パス処理の欠陥 and バッファオーバーフロー などに関し、一部は vendor impact data exposure を招き、vendor surface production workloads and vendor surface software deployment 関連の場面に影響します。
掲載データは公開脆弱性情報とセキュリティ公告に基づき、過去の暴露面と修補優先度の評価に利用できます。
| CVE | 概要 | ソース | CVSS 最大値 | EPSS（%） | 公開 | 更新 |
|---|---|---|---|---|---|---|
| CVE-2026-42006 | 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 exploi | [email protected] | 4.3 | 0.32% | 2026-05-12 | 2026-05-18 |
| CVE-2026-40020 | Attacker can use the IMAP SETACL command to inject the anyone permission to user's dovecot-acl file even if imap_acl_allow_anyone=no. This causes folders to be spammed to all users. The impact is limited to being able to spam folders to other users, no unexpected access is gained. Install to fixed version. No publicly available exploits are known. | [email protected] | 3.1 | 0.28% | 2026-05-12 | 2026-05-18 |
| CVE-2026-40016 | Attacker can upload a malicious Sieve script over ManageSieve service (or locally) to bypass configured CPU time limits for Sieve up to 130 times of the configured limit. Attacker can use this to degrade server performance and bypass configured CPU time limits for Sieve scripts. Install fixed version, or alternatively prevent direct access to Sieve scripts via ManageSieve or local access. No publicly available exploits are known. | [email protected] | 5.3 | 0.35% | 2026-05-12 | 2026-05-18 |
| CVE-2026-33603 | 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. | [email protected] | 6.8 | 0.23% | 2026-05-12 | 2026-05-18 |
| CVE-2026-27851 | 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. | [email protected] | 7.4 | 0.32% | 2026-05-12 | 2026-05-18 |
| CVE-2026-27860 | 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. | [email protected] | 3.7 | 0.29% | 2026-03-27 | 2026-04-29 |
| CVE-2026-27859 | 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. | [email protected] | 5.3 | 0.37% | 2026-03-27 | 2026-04-30 |
| CVE-2026-27858 | 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. | [email protected] | 7.5 | 0.46% | 2026-03-27 | 2026-04-30 |
| CVE-2026-27857 | 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 | [email protected] | 4.3 | 0.39% | 2026-03-27 | 2026-04-30 |
| CVE-2026-27856 | 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. | [email protected] | 7.4 | 0.29% | 2026-03-27 | 2026-04-29 |
| CVE-2026-27855 | 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 kno | [email protected] | 6.8 | 0.34% | 2026-03-27 | 2026-04-29 |
| CVE-2026-24031 | 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. | [email protected] | 7.7 | 0.29% | 2026-03-27 | 2026-04-29 |
| CVE-2026-0394 | 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 versi | [email protected] | 5.3 | 0.43% | 2026-03-27 | 2026-04-29 |
| CVE-2025-59032 | 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. | [email protected] | 7.5 | 0.41% | 2026-03-27 | 2026-04-30 |
| CVE-2025-59031 | 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 publicly available exploits are known. | [email protected] | 4.3 | 0.28% | 2026-03-27 | 2026-04-29 |
| CVE-2025-59028 | 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 publicly available exploits are known. | [email protected] | 5.3 | 0.45% | 2026-03-27 | 2026-04-30 |
| CVE-2022-30550 | An issue was discovered in the auth component in Dovecot 2.2 and 2.3 before 2.3.20. When two passdb configuration entries exist with the same driver and args settings, incorrect username_filter and mechanism settings can be applied to passdb definitions. These incorrectly applied settings can lead to an unintended security configuration and can permit privilege escalation in certain configurations. The documentation does not advise against the use of passdb definitions that have the same driver | [email protected] | 8.8 | 1.74% | 2022-07-17 | 2025-05-23 |
| CVE-2021-33515 | The submission service in Dovecot before 2.3.15 allows STARTTLS command injection in lib-smtp. Sensitive information can be redirected to an attacker-controlled address. | [email protected] | 4.8 | 2.84% | 2021-06-28 | 2024-11-21 |
| CVE-2020-28200 | The Sieve engine in Dovecot before 2.3.15 allows Uncontrolled Resource Consumption, as demonstrated by a situation with a complex regular expression for the regex extension. | [email protected] | 4.3 | 1.97% | 2021-06-28 | 2024-11-21 |
| CVE-2021-29157 | Dovecot before 2.3.15 allows ../ Path Traversal. An attacker with access to the local filesystem can trick OAuth2 authentication into using an HS256 validation key from an attacker-controlled location. This occurs during use of local JWT validation with the posix fs driver. | [email protected] | 7.5 | 0.47% | 2021-06-28 | 2024-11-21 |