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Mattermost ServerApplication · Mattermost

CVE-2022-0903

HIGH · 7.5 CVSS v3.1 Published 2022-03-10
Fix available
A fix is available. Upgrade to 5.37.8 / 6.1.3 or later.
See remediation →
84/100
Remediation priority · High
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
A call stack overflow bug in the SAML login feature in Mattermost server in versions up to and including 6.3.2 allows an attacker to crash the server via submitting a maliciously crafted POST body.

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

A call stack overflow vulnerability exists in the SAML login feature of Mattermost server versions up to 6.3.2. An attacker can trigger this by sending a maliciously crafted POST body to the SAML authentication endpoint, causing the server to crash due to stack overflow.

MitigationUpgrade Mattermost server to a version beyond 6.3.2 that contains the fix for this vulnerability.

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:< 5.37.8>= 6.0.0, < 6.1.3>= 6.2.0, < 6.2.3>= 6.3.0, < 6.3.3

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
High

CVSS:3.1/AV:N/AC:L/PR:N/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. Verify SAML authentication is enabled
    Check the Mattermost system console under Authentication > SAML or inspect the config.json file for 'SAMLEnabled' set to true. Also verify that at least one SAML plugin is configured and active.
    Affected if SAML authentication is enabled and configured in the Mattermost instance
  2. Determine the installed Mattermost Server version
    Access the Mattermost System Console by navigating to the Mattermost site and going to the product menu > About Mattermost, or run the command 'mattermost version' from the server CLI, or check the /opt/mattermost/version.txt file.
    Affected if The installed version falls within any of these ranges: < 5.37.8 OR >= 6.0.0 and < 6.1.3 OR >= 6.2.0 and < 6.2.3 OR >= 6.3.0 and < 6.3.3
  3. Confirm SAML authentication endpoint is externally accessible
    Verify that the Mattermost server is network-accessible and the SAML login endpoint (typically /login/sso/saml) is reachable from untrusted networks. Check firewall rules and reverse proxy configurations.
    Affected if The SAML endpoint is exposed to the internet or untrusted networks

An instance is affected if it has SAML authentication enabled, is running an affected version within the vulnerable ranges, and has the SAML endpoint accessible to attackers who can send malicious POST requests.

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 5.37.8 / 6.1.3 / 6.2.3 or later
Fixed in 5.37.86.1.36.2.3
Interim mitigation

Upgrade Mattermost server to a version beyond 6.3.2 that contains the fix for this vulnerability.

Recommended fix High confidence

Mattermost Server 5.37.8, 6.1.3, 6.2.3, or 6.3.3 (depending on your current major version branch)

  1. 1. Identify the currently running Mattermost Server version using the system console or CLI: `mattermost version`
  2. 2. Determine which upgrade path applies based on your current major version (5.x, 6.0.x, 6.2.x, or 6.3.x)
  3. 3. For Mattermost 5.x: Upgrade to version 5.37.8 or later
  4. 4. For Mattermost 6.0.x: Upgrade to version 6.1.3 or later
  5. 5. For Mattermost 6.2.x: Upgrade to version 6.2.3 or later
  6. 6. For Mattermost 6.3.x: Upgrade to version 6.3.3 or later
  7. 7. Follow standard Mattermost upgrade procedures: backup database and config, stop server, install new version, verify startup, test SAML login functionality
Caveat Standard Mattermost minor/patch upgrades are generally backward compatible; review release notes for any specific migration notes

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

Fix this in Mattermost Server Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing4.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,900
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,040.

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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-2022-0903 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