dbcve.org
MattermostApplication

CVE-2023-2193

CRITICAL · 9.1 CVSS v3.1 Published 2023-04-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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 invalidate existing authorization codes when deauthorizing an OAuth2 app, allowing an attacker possessing an authorization code to generate an access token.

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's OAuth2 implementation fails to invalidate authorization codes when a user deauthorizes an OAuth2 application. An attacker who has obtained a valid authorization code can still exchange it for an access token even after the legitimate user has revoked/deauthorized the application, maintaining persistent unauthorized access to the user's data through the OAuth2 integration.

MitigationMattermost must implement proper invalidation of all existing authorization codes when a user deauthorizes an OAuth2 app, ensuring that previously issued codes can no longer be exchanged for access tokens.

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:= 7.1.7= 7.7.3= 7.8.2= 7.9.1

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
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 Mattermost server version
    Run 'mattermost version' from the server CLI, or log into the System Console and navigate to About > Mattermost to view the version number
    Affected if Version is exactly 7.1.7, 7.7.3, 7.8.2, or 7.9.1
  2. Identify configured OAuth2 applications
    Log into the System Console and go to OAuth 2.0 > OAuth Apps, or query the API endpoint /api/v4/oauth-apps to list all registered OAuth2 applications
    Affected if Any OAuth2 applications are registered and the server version matches one of the affected versions listed above
  3. Review active OAuth2 access tokens
    In the System Console, navigate to OAuth 2.0 > Access Tokens and examine all issued access tokens for any that were generated before their corresponding application was authorized, or tokens that may remain active after deauthorization
    Affected if Active access tokens exist that should have been revoked but remain valid, particularly tokens from OAuth2 apps that users have deauthorized

A user is affected if their Mattermost server runs version 7.1.7, 7.7.3, 7.8.2, or 7.9.1 AND they have OAuth2 applications configured, as authorization codes remain valid after deauthorization in these versions.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Mattermost must implement proper invalidation of all existing authorization codes when a user deauthorizes an OAuth2 app, ensuring that previously issued codes can no longer be exchanged for access tokens.

Recommended fix Moderate confidence

Latest stable Mattermost Server (8.x line or latest 7.x security patch)

  1. 1. Back up your Mattermost database and configuration files before performing any upgrade.
  2. 2. Plan a maintenance window for the upgrade, as this will require a short service restart.
  3. 3. Download and install the latest stable Mattermost Server version (recommended: 8.x or the latest 7.x security release that includes the fix for CVE-2023-2193).
  4. 4. After upgrading, verify that OAuth2 applications can be properly deauthorized and that existing authorization codes are invalidated.
  5. 5. Review all existing OAuth2 authorized applications in System Console > Integrations > OAuth 2.0 and consider re-authorizing only trusted applications if needed.
Caveat Major version upgrades (e.g., 7.x to 8.x) may require database migrations and configuration changes; review Mattermost upgrade guides for breaking changes between major versions

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

Fix this in Mattermost Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,380
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,408.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-2193 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2023-2193 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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