CVE-2018-21264
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 · uneditedAn issue was discovered in Mattermost Server before 4.7.0, 4.6.2, and 4.5.2. It did not enforce the expiration date of a SAML response.
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 confidenceMattermost Server failed to validate the expiration timestamp in SAML authentication responses, allowing expired SAML tokens to be accepted for user authentication. This could permit unauthorized access using stale authentication tokens beyond their intended validity period.
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< 4.5.2>= 4.6.0, < 4.6.2= 4.7.0CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 checksWork through these to decide whether this CVE applies to you.
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Identify Mattermost Server versionAccess the Mattermost System Console, go to About > Mattermost, or run 'mattermost version' from the command line. Alternatively, check the /opt/mattermost/version.go file or the package metadata.Affected if The installed version is less than 4.5.2, OR between 4.6.0 and 4.6.2 (exclusive of 4.6.2), OR exactly 4.7.0
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Verify SAML authentication is configuredIn Mattermost System Console, navigate to Authentication > SAML 2.0. Check if SAML authentication is enabled and a SAML IdP is configured.Affected if SAML authentication is NOT enabled - the vulnerability only applies when SAML is the configured authentication method
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Inspect SAML IdP configuration for expiration settingsIn System Console under Authentication > SAML 2.0 > IdP Metadata, or by reviewing the uploaded IdP metadata XML file, look for 'SessionNotOnOrAfter' attributes or token validity period settings.Affected if No explicit expiration validation is configured in the SAML settings, or the IdP metadata lacks time-bound session attributes
You are affected if your Mattermost Server version falls within the vulnerable ranges AND SAML authentication is enabled, regardless of SAML expiration configuration since the code failed to validate timestamps at all in affected versions.
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 data4.5.24.6.2
Upgrade Mattermost Server to version 4.7.0, 4.6.2, or 4.5.2 or later which includes proper SAML response expiration enforcement, or enable explicit expiration validation in the SAML configuration if available in affected versions.
- Consultation3.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2018-21264 — 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-2018-21264 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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- Version or environment caveats, and links to real fixes
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