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Mattermost ServerApplication · Mattermost

CVE-2022-3147

MEDIUM · 6.5 CVSS v3.1 Published 2022-09-09
Fix available
A fix is available. Upgrade to 7.1.0 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 version 7.0.x and earlier fails to sufficiently limit the in-memory sizes of concurrently uploaded JPEG images, which allows authenticated users to cause resource exhaustion on specific system configurations, resulting in server-side Denial of Service.

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 versions 7.0.x and earlier lack sufficient in-memory size limits for concurrently uploaded JPEG images, allowing authenticated users to exhaust server resources by uploading large images that consume excessive memory during processing, leading to denial of service.

MitigationUpgrade to a patched Mattermost version (7.1 or later), or implement application-level limits on image dimensions and file size before in-memory processing, combined with rate limiting on upload endpoints.

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:< 7.1.0

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

CVSS:3.1/AV:N/AC:L/PR:L/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
    Check for Mattermost processes running (ps aux | grep mattermost) or locate mattermost binary (which mattermost or find /opt -name mattermost 2>/dev/null)
    Affected if No Mattermost Server found - not applicable
  2. Determine installed Mattermost version
    Run 'mattermost version' if binary accessible, or check the Mattermost about page in the System Console (System Console > About), or inspect /opt/mattermost/version.txt if present
    Affected if Version is 7.0.x or earlier, or any version below 7.1.0 - potentially affected
  3. Verify image upload is enabled for authenticated users
    Check Mattermost configuration file (config.json) for 'FileSettings.EnableFileAttachments' set to true, and confirm 'MaxFileSize' is either unset or set to a large value allowing large uploads
    Affected if File attachments enabled with no strict size limits - vulnerable condition present
  4. Check JPEG processing configuration
    Inspect Mattermost System Console settings under Posts > Image Proxy, or check if ImageProxy setting in config.json is disabled or not configured to limit in-memory image processing
    Affected if No in-memory limits configured for image processing - vulnerable to DoS

If running Mattermost Server versions before 7.1.0 with file attachments enabled, the server is affected by this DoS vulnerability via large JPEG uploads.

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 7.1.0 or later
Fixed in 7.1.0
Interim mitigation

Upgrade to a patched Mattermost version (7.1 or later), or implement application-level limits on image dimensions and file size before in-memory processing, combined with rate limiting on upload endpoints.

Recommended fix High confidence

7.1.0

  1. 1. Backup your Mattermost database and configuration files before upgrading
  2. 2. Download Mattermost Server version 7.1.0 from the official Mattermost downloads page
  3. 3. Stop the Mattermost Server service
  4. 4. Upgrade the Mattermost Server installation using your package manager or by replacing the binary/service
  5. 5. Verify the upgrade was successful by checking the server version in the system console
  6. 6. Restart the Mattermost Server service
  7. 7. Test that file uploads (especially JPEG images) function correctly and that the server remains stable under concurrent upload scenarios
Caveat Review the Mattermost 7.1.0 release notes for any breaking changes or deprecations before upgrading, particularly if migrating from versions earlier than 7.0.x

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

Fix this in Mattermost Server Scoped from the published advisory
  • Consultation3.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
17.0 hours of engineering $3,000
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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-2022-3147 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