CVE-2023-3581
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 fails to properly validate the origin of a websocket connection allowing a MITM attacker on Mattermost to access the websocket APIs.
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 confidenceMattermost fails to properly validate the Origin header in websocket connections, allowing a man-in-the-middle attacker on the network to send malicious requests through the websocket API by spoofing or omitting the Origin header, potentially gaining unauthorized access to user data or actions.
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>= 7.8.0, < 7.8.7>= 7.9.0, < 7.9.5>= 7.10.0, < 7.10.3CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/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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Determine installed Mattermost Server versionLog into the Mattermost system console or check the /about page, or run 'mattermost version' from the command line if you have CLI accessAffected if The version displayed falls within 7.8.0-7.8.6, 7.9.0-7.9.4, or 7.10.0-7.10.2
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Confirm websocket connections are enabledCheck the Mattermost config.json file for 'EnableWebSocket' setting set to true, or verify via System Console > Environment > WebsocketAffected if Websockets are enabled (this is the default setting)
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.
dbcve · scoped7.8.77.9.57.10.3
Implement strict Origin header validation in the websocket handshake handler to reject connections from untrusted origins, and consider using CSRF tokens for additional protection.
7.10.3 or later (minimum fixed versions: 7.8.7, 7.9.5, or 7.10.3)
- Backup your Mattermost Server data and configuration
- Stop the Mattermost Server service
- Upgrade Mattermost Server to version 7.10.3 or later (7.8.7, 7.9.5, or 7.10.3+ contain the fix)
- Verify the upgrade was successful by checking the server version
- Restart the Mattermost Server service
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 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 $4,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-3581 — 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-2023-3581 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
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