CVE-2021-37861
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 · uneditedMattermost 6.0.2 and earlier fails to sufficiently sanitize user's password in audit logs when user creation fails.
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 confidenceIn Mattermost 6.0.2 and earlier, when user creation fails (e.g., due to validation errors), the user's password is written to audit logs without proper sanitization, exposing sensitive credential data in plain text.
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<= 6.0.2CVSS 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
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/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 checksWork through these to decide whether this CVE applies to you.
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Determine your Mattermost server versionAccess the Mattermost System Console or check the version via the Mattermost server logs, API endpoint, or package manager used for installation (e.g., apt, yum, docker image tag)Affected if The installed version is 6.0.2 or earlier
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Confirm audit logging is enabledCheck the Mattermost configuration file (config.json) for the 'LogSettings.Enable' setting, or verify via the System Console under Environment > LoggingAffected if Audit logging is enabled and logs are being written to disk
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Inspect audit logs for user creation eventsExamine Mattermost log files (typically located in /var/log/mattermost/ or the logs directory configured in config.json) for entries related to failed user creation attempts. Search for patterns like 'create user', 'user creation failed', or API endpoint calls to /usersAffected if Log entries exist for failed user creation attempts and logs are retained from version 6.0.2 or earlier
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Search for plaintext passwords in logsUse grep or a text search tool to search log files for password strings appearing in plain text near user creation failure events. Look for 'password' field values that appear in cleartext rather than maskedAffected if Plaintext password strings are found in logs during failed user creation operations
Your environment is affected if you run Mattermost version 6.0.2 or earlier, have audit logging enabled, and retain logs from periods where user creation failures occurred, as passwords may have been recorded in plaintext.
Generated from the published advisory. Verify against your own configuration.
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 dataUpgrade to Mattermost 6.0.3 or later which includes proper password sanitization in audit logs. Additionally, audit existing logs for exposed passwords and rotate any credentials that may have been logged.
- Consultation3.0 h
- Implementation3.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-37861 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-37861 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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