CVE-2019-20868
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 5.11.0. Invite IDs were improperly generated.
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 confidenceThe vulnerability involves improper generation of invite IDs in Mattermost Server versions prior to 5.11.0, likely resulting in insufficient entropy or predictability that could allow attackers to guess valid invite IDs and gain unauthorized access to teams/channels.
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< 4.10.8>= 5.7.0, < 5.7.3>= 5.8.0, < 5.8.1= 5.9.0CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 checksWork through these to decide whether this CVE applies to you.
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Determine installed Mattermost Server versionCheck the version via the system console (About > Mattermost Version), the config.json file (look for 'Version' field), or by running 'mattermost version' from the command line if you have CLI accessAffected if The version is less than 4.10.8, OR between 5.7.0 and 5.7.2 inclusive, OR between 5.8.0 and 5.8.0 inclusive, OR exactly 5.9.0
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Verify invite link feature is in useCheck if any team invitations have been created by reviewing team settings in the Mattermost UI (Team Settings > Invite Members) or by querying the database for entries in the InviteTables table if database access is availableAffected if Invite links have been generated and are active or were recently active in the affected version range
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Check invite ID format if accessibleIf you can view an active invite link (typically in the format of yourserver.com/signup_user_complete/?id=XXXXX), examine the invite ID portion - note that this check is informational only as the exact weak format is not publicly documentedAffected if The invite ID appears unusually short or follows a simple sequential pattern rather than a long random string
You are affected if your Mattermost Server version falls within the vulnerable ranges AND you have used team/channel invite links.
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 data4.10.85.7.35.8.1
Upgrade Mattermost Server to version 5.11.0 or later which implements properly generated invite IDs using cryptographically secure random generation.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-20868 — 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-2019-20868 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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