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Mattermost ServerApplication · Mattermost

CVE-2025-31947

MEDIUM · 5.3 CVSS v3.1 Published 2025-05-15
Fix available
A fix is available. Upgrade to 9.11.12 / 10.4.5 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
Mattermost versions 10.6.x <= 10.6.1, 10.5.x <= 10.5.2, 10.4.x <= 10.4.4, 9.11.x <= 9.11.11 fail to lockout LDAP users following repeated login failures, which allows attackers to lock external LDAP accounts through repeated login failures through Mattermost.

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

Mattermost fails to properly implement account lockout for LDAP-authenticated users, allowing attackers to cause the external LDAP directory to lock out user accounts by making repeated failed login attempts through Mattermost. The application does not properly track or throttle LDAP authentication failures before passing them to the LDAP server, enabling a denial-of-service attack against LDAP-backed accounts.

MitigationUpdate Mattermost to a patched version that properly handles LDAP authentication failure tracking and lockout. Alternatively, configure the LDAP server's account lockout policy to be less aggressive or implement rate limiting at the Mattermost level before LDAP authentication attempts.

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
Mattermost ServerApplication
Affected:>= 9.11.0, < 9.11.12>= 10.4.0, < 10.4.5>= 10.5.0, < 10.5.3>= 10.6.0, < 10.6.2

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
None
Integrity
None
Availability
Low

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

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 the Mattermost Server version
    Access the Mattermost System Console > About > Mattermost or use the /about command in the desktop or web app to view the exact version number installed.
    Affected if The installed version falls within any of these ranges: 9.11.0 through 9.11.11, 10.4.0 through 10.4.4, 10.5.0 through 10.5.2, or 10.6.0 through 10.6.1.
  2. Verify LDAP authentication is enabled
    Navigate to the Mattermost System Console > Authentication > LDAP and confirm that LDAP authentication is turned on and configured with an LDAP server.
    Affected if LDAP authentication is enabled and users are authenticated against an external LDAP directory.
  3. Confirm rate limiting for LDAP login attempts
    Check the System Console > Rate Limiting settings to see if rate limiting is configured specifically for LDAP or authentication endpoints.
    Affected if No rate limiting or throttling is configured for failed login attempts before they are passed to the LDAP server.
  4. Check LDAP account lockout policy settings
    Review the LDAP server configuration to understand the account lockout threshold and whether Mattermost is tracking failed attempts before forwarding them.
    Affected if The LDAP server has a strict lockout policy and Mattermost forwards authentication failures without local tracking or throttling.

You are affected if your Mattermost Server version is in the affected list AND LDAP authentication is enabled without proper rate limiting configured between Mattermost and the LDAP server.

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 9.11.12 / 10.4.5 / 10.5.3 or later
Fixed in 9.11.1210.4.510.5.3
Interim mitigation

Update Mattermost to a patched version that properly handles LDAP authentication failure tracking and lockout. Alternatively, configure the LDAP server's account lockout policy to be less aggressive or implement rate limiting at the Mattermost level before LDAP authentication attempts.

Recommended fix High confidence

Upgrade to Mattermost Server 9.11.12, 10.4.5, 10.5.3, or 10.6.2 (or later) depending on your current major version branch

  1. Identify the current Mattermost Server version by checking the system console or running 'mattermost version'
  2. Plan for upgrade during a maintenance window to minimize user impact
  3. Back up the Mattermost database and configuration files before upgrading
  4. Upgrade to the fixed version: 9.11.12 (if on 9.11.x), 10.4.5 (if on 10.4.x), 10.5.3 (if on 10.5.x), or 10.6.2 (if on 10.6.x)
  5. After upgrade, verify that LDAP login failure lockout is functioning by testing repeated failed login attempts
  6. Confirm the upgrade was successful by checking the version in the system console
Caveat Review Mattermost release notes for any breaking changes between your current version and target version, particularly when upgrading across major version branches (9.x to 10.x)

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

Fix this in Mattermost Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,880
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,808.

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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-2025-31947 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