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Mattermost ServerApplication · Mattermost

CVE-2025-31363

MEDIUM · 6.5 CVSS v3.1 Published 2025-04-16
Fix available
A fix is available. Upgrade to 9.11.10 / 10.4.3 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable 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 10.4.x <= 10.4.2, 10.5.x <= 10.5.0, 9.11.x <= 9.11.9 fail to restrict domains the LLM can request to contact upstream which allows an authenticated user to exfiltrate data from an arbitrary server accessible to the victim via performing a prompt injection in the AI plugin's Jira tool.

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's AI plugin Jira tool fails to restrict domains the LLM can request, allowing authenticated users to perform prompt injection that tricks the LLM into making requests to arbitrary upstream servers accessible to the victim, enabling data exfiltration from internal systems.

MitigationUpgrade to Mattermost 10.4.3, 10.5.1, or 9.11.10 or later to receive the patch. Alternatively, restrict network access to internal resources and monitor for suspicious prompt injection patterns.

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, < 9.11.10>= 10.4.0, < 10.4.3= 10.5.0

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/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. Identify Mattermost Server version
    Run 'mattermost version' or check the /api/v4/system/config/ endpoint, or inspect the version displayed in the Mattermost System Console under About > Mattermost
    Affected if The installed version is 9.11.0 through 9.11.9, 10.4.0 through 10.4.2, or exactly 10.5.0
  2. Confirm AI plugin is installed
    Navigate to System Console > Plugins > Plugin Management, or query the /api/v1/plugins endpoint. Look for 'mattermost-ai' or similar AI-related plugins
    Affected if An AI plugin is installed and enabled
  3. Verify Jira AI tool is enabled
    Check the AI plugin configuration in System Console > Plugins > [AI Plugin] > Settings, or examine the plugin's active tools list. The 'jira' tool must be listed as active
    Affected if The Jira tool is listed as an active tool within the AI plugin configuration
  4. Assess network exposure
    Review Mattermost server network configuration and firewall rules to determine if the server can reach internal network segments or sensitive internal services
    Affected if The Mattermost server has outbound network access to internal systems that should not be externally reachable
  5. Review plugin logs for suspicious activity
    Check Mattermost logs (typically in /var/log/mattermost/ or via System Console > logs) and plugin-specific logs for unusual outbound request patterns or prompt injection indicators
    Affected if Logs show outbound HTTP/HTTPS requests from the AI plugin to unexpected internal domains or IP addresses

You are affected if your Mattermost Server version falls within 9.11.0-9.11.9, 10.4.0-10.4.2, or 10.5.0 AND the AI plugin with the Jira tool is enabled and your server can access internal resources.

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 9.11.10 / 10.4.3 or later
Fixed in 9.11.1010.4.3
Interim mitigation

Upgrade to Mattermost 10.4.3, 10.5.1, or 9.11.10 or later to receive the patch. Alternatively, restrict network access to internal resources and monitor for suspicious prompt injection patterns.

Recommended fix High confidence

Mattermost Server 9.11.10+, 10.4.3+, or 10.5.1+ (next patch release beyond 10.5.0)

  1. Identify the current Mattermost Server version by checking the system console or running 'mattermost version'
  2. For versions 9.11.0 through 9.11.9: upgrade to Mattermost Server 9.11.10 or later
  3. For versions 10.4.0 through 10.4.2: upgrade to Mattermost Server 10.4.3 or later
  4. For version 10.5.0: upgrade to the next available patch release (10.5.1 or later)
  5. After upgrading, verify the fix by checking the Mattermost Server version and confirming the AI plugin's domain restrictions are enforced
  6. Review user permissions and audit access to the AI plugin to ensure no unauthorized data exfiltration occurred prior to patching
Caveat Standard Mattermost upgrade considerations apply - review release notes for database migration requirements and deprecated features

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

Fix this in Mattermost Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,800
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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-2025-31363 in production — separate from our analysis above.

No notes yet

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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