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DovecotApplication

CVE-2026-0394

MEDIUM · 5.3 CVSS v3.1 Published 2026-03-27
Fix available
A fix is available. Upgrade to 2.4.0 / 3.1.0 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Dovecot contains a path traversal vulnerability when configured to use per-domain passwd files placed one path component above /etc, or when slash is added to allowed characters. By providing a malicious domain component that is a directory partial (e.g., '../../../etc/passwd'), an attacker can read sensitive passwd files and potentially authenticate as arbitrary users or make system users appear as valid mail users.

MitigationUpgrade to the fixed Dovecot version, or relocate per-domain passwd files to a non-system location like /etc/dovecot/auth/%d, or migrate to an authentication scheme that does not rely on file-system paths.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
DovecotApplication
Affected:< 2.4.0
DovecotApplication
Affected:< 3.1.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed Dovecot version
    Run 'dovecot --version' or check the package manager (e.g., 'rpm -q dovecot' or 'dpkg -l dovecot')
    Affected if The version is below 2.4.0 for standard Dovecot or below 3.1.0 for Open Xchange Dovecot
  2. Identify passdb configuration using passwd-file driver
    Inspect dovecot configuration files (typically in /etc/dovecot/) for 'passdb { driver=passwd-file }' or similar passdb entries. Look for 'scheme' or 'args' settings that reference per-domain file paths using %d
    Affected if A passdb entry uses passwd-file driver with per-domain path resolution (e.g., /etc/dovecot/%d/passwd or similar)
  3. Examine the per-domain passwd file path location
    Locate the 'file_path' or 'args' parameter in the passdb or userdb configuration. Determine if the base directory is placed one path component above /etc (for example, if files are at /etc/%d/passwd, the parent is /etc which is one component above a system root)
    Affected if The base path for per-domain passwd files resolves to a location where traversal could reach /etc or system directories (e.g., path starts with /etc or places domain data directly under /etc)
  4. Check for user_filter or allowed characters configuration
    Search configuration files for 'user_filter', 'auth_username_format', or 'allowed_chars' settings within passdb or userdb blocks. Verify if 'slash' is explicitly added to allowed characters
    Affected if The configuration allows slash characters in usernames/filters, or the user_filter setting could accept domain components with path traversal sequences

You are affected if Dovecot version is below 2.4.0 (or below 3.1.0 for OX Dovecot) AND you use per-domain passwd files with a base path that could be traversed to reach /etc or system directories, or if slash characters are allowed in the authentication username filter.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.4.0 / 3.1.0 or later
Fixed in 2.4.03.1.0
Interim mitigation

Upgrade to the fixed Dovecot version, or relocate per-domain passwd files to a non-system location like /etc/dovecot/auth/%d, or migrate to an authentication scheme that does not rely on file-system paths.

Recommended fix High confidence

Dovecot 2.4.0 (2.x branch) or Dovecot 3.1.0 (3.x branch)

  1. Upgrade to Dovecot 2.4.0 or later if using the 2.x branch
  2. Upgrade to Dovecot 3.1.0 or later if using the 3.x branch
  3. After upgrade, verify that per-domain passwd file configurations still function correctly
  4. Alternatively, if upgrade is not immediately feasible, move per-domain passwd files from their current location to a non-system directory such as /etc/dovecot/auth/%d
  5. Alternatively, migrate to an authentication scheme that does not rely on file paths (e.g., LDAP, SQL database)
Caveat Review configuration changes between current version and target version; test authentication flows thoroughly before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Dovecot Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-0394 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data