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Mattermost ServerApplication · Mattermost

CVE-2023-49607

HIGH · 7.5 CVSS v3.1 Published 2023-12-12
Fix available
A fix is available. Upgrade to after 9.2.1 or later.
See remediation →
84/100
Remediation priority · High
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 fails to validate the type of the "reminder" body request parameter allowing an attacker to crash the Playbook Plugin when updating the status dialog.

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

The Mattermost Playbook Plugin lacks proper type validation on the 'reminder' request parameter when updating the status dialog. An attacker can send a request with an incorrectly-typed reminder value (e.g., an object or array instead of the expected integer/string), causing the plugin to crash due to improper type handling.

MitigationApply the vendor patch for CVE-2023-49607 which adds proper type validation for the reminder parameter in the Playbook Plugin's status dialog update handler.

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:<= 7.8.14>= 8.0.0, <= 8.1.5>= 9.0.0, <= 9.0.3>= 9.1.0, <= 9.1.2>= 9.2.0, <= 9.2.1= 9.1.1

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
High

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

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 installation
    Locate the Mattermost Server binary or service. Common paths: /opt/mattermost, or check for mattermost service running via 'systemctl status mattermost' or 'ps aux | grep mattermost'
    Affected if Mattermost Server is not installed - not affected
  2. Determine installed Mattermost Server version
    Run 'mattermost version' from the Mattermost bin directory, or check the version file in the Mattermost installation directory, or query the /api/v4/system endpoint with a valid API token
    Affected if Cannot determine version - further investigation needed
  3. Compare version against affected ranges
    Check if the installed version falls within any of these ranges: <= 7.8.14, >= 8.0.0 AND <= 8.1.5, >= 9.0.0 AND <= 9.0.3, >= 9.1.0 AND <= 9.1.2, >= 9.2.0 AND <= 9.2.1, OR exactly 9.1.1
    Affected if Version is within any of these ranges - affected
  4. Verify Playbooks plugin is enabled
    Check Mattermost plugin list via System Console or use 'mattermost plugin list' CLI command to confirm the Playbooks plugin is installed and enabled
    Affected if Playbooks plugin is not enabled - not vulnerable as the attack surface does not exist
  5. Identify if status dialog functionality is accessible
    The vulnerability exists in the Playbook status dialog update endpoint. Verify Playbooks are in use by checking for playbook creations or memberships via Mattermost API or UI
    Affected if No playbooks are created or used - attack surface is minimal though version may still be affected

The environment is affected if Mattermost Server is running with a version matching the affected ranges AND the Playbooks plugin is enabled.

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 a release after 9.2.1
Interim mitigation

Apply the vendor patch for CVE-2023-49607 which adds proper type validation for the reminder parameter in the Playbook Plugin's status dialog update handler.

Recommended fix Moderate confidence

Mattermost Server 9.2.0 or later

  1. 1. Back up your Mattermost Server database and configuration files before upgrading.
  2. 2. Review Mattermost's upgrade documentation for your current version path.
  3. 3. Upgrade Mattermost Server to version 9.2.0 or later (the first version after the affected range 9.1.0-9.1.2).
  4. 4. Verify the Playbook Plugin is updated as part of the upgrade.
  5. 5. Test the status dialog functionality in Playbooks to confirm the fix is applied.
  6. 6. Monitor system logs for any errors related to the reminder parameter.
Caveat Check Mattermost upgrade notes for potential breaking changes between 9.x versions, especially regarding Playbook plugin API changes

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
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.

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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-2023-49607 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