GitLabApplication
CVE-2020-13270
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 · uneditedMissing permission check on fork relation creation in GitLab CE/EE 11.3 and later through 13.0.1 allows guest users to create a fork relation on restricted public projects via API
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 confidenceMissing authorization check in GitLab's API allows guest users to create fork relations on restricted public projects. Guest users, who should have read-only or no access to private content, can exploit the fork relation API endpoint to establish fork relationships on projects that should be restricted.
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
GitLabApplication
>= 11.3.0, < 11.9.8>= 11.3.0, < 12.9.8>= 12.10.0, < 12.10.7>= 13.0.0, < 13.0.1CVSS 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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Determine installed GitLab versionLog into the GitLab admin interface and navigate to the Admin Area > Overview > Dashboard, or use the API endpoint GET /api/v4/version to retrieve the version numberAffected if The version falls within any of these ranges: 11.3.0 to 11.9.7, 11.3.0 to 12.9.7, 12.10.0 to 12.10.6, or 13.0.0
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Verify API endpoint accessibilityConfirm that the GitLab API is accessible at your instance's /api/v4/ endpoint. This is enabled by default on standard GitLab installationsAffected if The API is reachable without additional network restrictions
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Identify guest user accountsIn the Admin Area, go to Users and filter or search for users with the Guest role, or query the API endpoint GET /api/v4/users to list accounts and check their access levelsAffected if Any guest user accounts exist in the system
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Check for unauthorized fork relationsUse an authenticated session with a guest-level user account to make a POST request to /api/v4/projects/:id/fork/:forked_from_id to attempt creating a fork relationship on a restricted project. Review the response code and any created fork relations in the project settingsAffected if The API returns a successful response (200 or 201) and allows a guest user to create fork relations on projects they should not have access to modify
You are affected if your GitLab version is within the affected ranges listed above and your API is accessible to guest users who can successfully create fork relations on restricted projects.
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 data11.9.812.9.812.10.7
Upgrade GitLab to version 13.0.2 or later. Alternatively, implement API request filtering at the gateway layer to block fork relation API calls from unauthenticated or guest-level users until the upgrade can be performed.
Fix this in GitLab
Scoped from the published advisory
- Consultation4.0 h
- Implementation6.0 h
- Testing8.0 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 $6,080.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-13270 — 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-2020-13270 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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