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MattermostApplication

CVE-2023-48369

MEDIUM · 5.3 CVSS v3.1 Published 2023-11-27
Fix available
A fix is available. Upgrade to after 9.0.1 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 fails to limit the log size of server logs allowing an attacker sending specially crafted requests to different endpoints to potentially overflow the log.

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 · moderate confidence

Mattermost server does not implement proper log size limits, allowing an attacker to send specially crafted requests to various endpoints that can overflow the server logs, potentially causing denial of service through disk exhaustion or log processing issues.

MitigationImplement log size limits and automatic log rotation, validate/sanitize input before logging to prevent log injection, and consider rate limiting on endpoints that generate verbose logging.

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
MattermostApplication
Affected:<= 7.8.12>= 8.0.0, <= 8.1.3>= 9.0.0, <= 9.0.1= 9.1.0

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
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. Identify Mattermost server version
    Run 'mattermost version' or check the Mattermost installation directory for version information, typically found in the about section of the System Console or via the API endpoint /api/v4/system/analytics/0
    Affected if The installed version falls within <= 7.8.12, >= 8.0.0 and <= 8.1.3, >= 9.0.0 and <= 9.0.1, or equals 9.1.0
  2. Locate Mattermost log files
    Check the Mattermost data directory for log files. Default paths include /var/log/mattermost/ or the logs/ subdirectory within the Mattermost installation. Check the configuration file (config.json) for the LogFileSettings location
    Affected if Log files exist in locations without configured size limits or rotation policies
  3. Verify log file rotation configuration
    Examine the Mattermost config.json file for 'LogSettings' > 'EnableFileLogging' and 'LogSettings' > 'FileLevel' settings. Check if 'MaxSizeMbc' is configured. Also check system rotation tools like logrotate for any configuration targeting mattermost logs
    Affected if No log rotation is configured, 'MaxSizeMbc' is not set or is set to an excessively large value, and no external rotation mechanism exists
  4. Inspect log file sizes
    Use 'ls -lh' or 'du -sh' on the identified log files to check their current sizes. Monitor over a short period if possible
    Affected if Log files are growing unboundedly or have reached unusually large sizes relative to expected traffic
  5. Check for log injection protection
    Review Mattermost configuration or proxy settings for input validation or sanitization applied before logging. Check if the logging mechanism handles special characters or newline characters in input parameters
    Affected if Input is logged without sanitization and no validation layer exists before logging

A user is affected if their Mattermost version is one of the vulnerable releases AND log size limits or rotation are not properly configured, allowing unbounded log growth.

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 9.0.1
Interim mitigation

Implement log size limits and automatic log rotation, validate/sanitize input before logging to prevent log injection, and consider rate limiting on endpoints that generate verbose logging.

Recommended fix Moderate confidence

Upgrade to 7.8.13 or later for 7.x, 8.1.4 or later for 8.x, 9.0.2 or later for 9.0.x, or 9.2.0 or later for 9.x

  1. 1. Identify your current Mattermost server version from the system console or logs
  2. 2. Visit the official Mattermost security updates page at mattermost.com to obtain the specific fixed version for your release line
  3. 3. Review the security release notes for the fixed version to understand changes
  4. 4. Back up your Mattermost database and configuration files
  5. 5. Upgrade Mattermost server to the fixed version (7.8.13+, 8.1.4+, 9.0.2+, or 9.2.0+)
  6. 6. Verify the upgrade was successful by checking the server version in the system console
  7. 7. Monitor disk usage to confirm log files are being properly managed
Caveat Check release notes for potential breaking changes between your current version and the target version before upgrading

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

Fix this in Mattermost 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-2023-48369 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