CVE-2017-18917
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 3.8.2, 3.7.5, and 3.6.7. Weak hashing was used for e-mail invitations, OAuth, and e-mail verification tokens.
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 Server versions before 3.8.2, 3.7.5, and 3.6.7 used weak hashing algorithms (likely MD5 or unsalted SHA1) to generate security tokens for email invitations, OAuth flows, and email verification. This allows attackers to potentially brute-force or rainbow-table attack these tokens to hijack accounts or bypass authentication.
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>= 3.6.0, < 3.6.7>= 3.7.0, < 3.7.5>= 3.8.0, < 3.8.2CVSS 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 installed Mattermost Server versionLog into the Mattermost System Console and navigate to About > Mattermost, or run 'mattermost version' from the server CLIAffected if Version is 3.6.0 through 3.6.6, 3.7.0 through 3.7.4, or 3.8.0 through 3.8.1
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Verify version is within affected rangesCompare your installed version number against the affected ranges: 3.6.x versions below 3.6.7, 3.7.x versions below 3.7.5, and 3.8.x versions below 3.8.2Affected if Your version falls within any of these ranges: >=3.6.0 and <3.6.7, or >=3.7.0 and <3.7.5, or >=3.8.0 and <3.8.2
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Confirm active email invitation or OAuth tokens existCheck the database table named something like 'ir_channel_member_history' or 'sessions' for recent invitation links that have not yet been used, or check for pending OAuth authorization flows in the databaseAffected if Any unused or pending invitation tokens, OAuth flows, or email verification tokens created by this server exist in the system
You are affected if your Mattermost Server version is 3.6.0-3.6.6, 3.7.0-3.7.4, or 3.8.0-3.8.1 and you have any email invitation, OAuth, or email verification tokens generated by the system that have not yet been consumed.
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 data3.6.73.7.53.8.2
Upgrade to Mattermost Server 3.8.2, 3.7.5, 3.6.7 or later. After upgrading, invalidate all existing invitation, OAuth, and email verification tokens to force regeneration with the stronger hashing algorithm.
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-18917 — 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-2017-18917 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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