Mattermost DesktopApplication · Mattermost

CVE-2023-5339

MEDIUM · 5.5 CVSS v3.1 Published 2023-10-17
Fix available
A fix is available. Upgrade to after 5.4.0 or later.
See remediation →
57/100
Remediation priority · Elevated
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 Desktop fails to set an appropriate log level during initial run after fresh installation resulting in logging all keystrokes including password entry being logged. 

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 Desktop fails to set an appropriate log level during the initial run after a fresh installation, causing all keystrokes including password entries to be written to log files. This exposes sensitive user credentials through verbose logging.

MitigationUsers should check and clear any log files created during the initial run to remove potentially exposed credentials. The vendor should patch the application to initialize the correct log level (e.g., WARNING or ERROR) before processing any user input.

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 DesktopApplication
Affected:<= 5.4.0

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
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/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. Check installed Mattermost Desktop version
    Open the application and navigate to Help > About Mattermost Desktop, or check the application metadata in your system to determine the exact version number
    Affected if The installed version is 5.4.0 or any earlier version (the vulnerability affects versions <= 5.4.0)
  2. Locate log files created during initial run
    Search for Mattermost Desktop log files in the user application data directory - look for any log files with timestamps corresponding to the first time the application was launched after installation
    Affected if Log files exist and were created during the initial run of the application
  3. Inspect log file contents for sensitive data
    Open the log files using a text editor and search for patterns that indicate password entries or other sensitive keystrokes - look for strings that may resemble credentials, authentication tokens, or personal data entered during login
    Affected if Log files contain plaintext passwords, authentication credentials, or other sensitive user input that should not have been recorded
  4. Verify verbose logging was active during initial run
    Examine log file entries near the timestamp of first launch - check if the log level was set to DEBUG, TRACE, or a similarly verbose level that would capture all keystrokes
    Affected if The log level during initial run was set to a verbose setting (such as DEBUG or equivalent) that would log all user input

A user is affected if they are running Mattermost Desktop version 5.4.0 or earlier and log files from the initial run contain plaintext passwords or sensitive credentials that were typed during the first login attempt.

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.

From vendor data
Upgrade available Upgrade to a release after 5.4.0
Interim mitigation

Users should check and clear any log files created during the initial run to remove potentially exposed credentials. The vendor should patch the application to initialize the correct log level (e.g., WARNING or ERROR) before processing any user input.

Fix this in Mattermost Desktop Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-5339 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2023-5339 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