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GitLabApplication

CVE-2023-2181

MEDIUM · 6.5 CVSS v3.1 Published 2023-05-12
Fix available
A fix is available. Upgrade to 15.9.8 / 15.10.7 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

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 · unedited
An issue has been discovered in GitLab affecting all versions before 15.9.8, 15.10.0 before 15.10.7, and 15.11.0 before 15.11.3. A malicious developer could use a git feature called refs/replace to smuggle content into a merge request which would not be visible during review in the UI.

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 confidence

A malicious developer can exploit git's refs/replace feature to smuggle hidden content into a merge request that is invisible during UI-based code review, effectively bypassing the code review process. This allows un-reviewed or malicious code to be merged without reviewers seeing the actual changes.

MitigationUpgrade GitLab to version 15.9.8, 15.10.7, or 15.11.3 or later to patch this code review bypass vulnerability.

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
Affected:< 15.9.8>= 15.10.0, < 15.10.7>= 15.11.0, < 15.11.3

CVSS 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
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify GitLab installation version
    Check your GitLab instance version by navigating to the Admin Area (Admin > Overview > Dashboard) or by running `gitlab-rake gitlab:env:info` on the server. Compare the installed version number against the affected ranges: < 15.9.8, >= 15.10.0 and < 15.10.7, >= 15.11.0 and < 15.11.3.
    Affected if The installed version falls within any of the three affected ranges provided.
  2. Audit git replace refs in repositories
    For each repository that may accept merge requests, inspect for replace refs by running `git fsck --full` or checking the `refs/replace/` namespace with `git for-each-ref refs/replace/`. Look for any replace refs that may be pointing to alternate commit objects.
    Affected if Any replace refs exist in repositories that could be used to substitute different commit content during merge request display.
  3. Review merge request diffs against direct git diffs
    Select recent merge requests and compare the changes shown in the GitLab web UI against the actual git diff obtained via command line (`git diff <base>..<head>`) or via API. Flag any discrepancies where UI shows fewer changes than git reports.
    Affected if The GitLab UI displays different content than what exists in the actual git commit history.
  4. Check for untrusted commit signatures in merge requests
    Review merge requests that contain commits with replace refs by examining commit SHAs directly in git rather than through the GitLab interface. Look for commits with different parents or content than what the merge request UI presents.
    Affected if Commits in merge requests contain refs/replace objects that alter their displayed content.

Your environment is affected if you run a GitLab version within the specified ranges AND your repositories accept merge requests that could contain git replace refs.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 15.9.8 / 15.10.7 / 15.11.3 or later
Fixed in 15.9.815.10.715.11.3
Interim mitigation

Upgrade GitLab to version 15.9.8, 15.10.7, or 15.11.3 or later to patch this code review bypass vulnerability.

Recommended fix High confidence

GitLab 15.11.3 or later (or 15.10.7 for 15.10.x line, or 15.9.8 for 15.9.x line)

  1. Backup your GitLab instance data before upgrading
  2. Plan maintenance window as upgrade requires service restart
  3. For installations using OMNIBUS packages: stop GitLab services with 'gitlab-ctl stop'
  4. Upgrade GitLab to version 15.11.3 or later using your package manager (e.g., 'apt-get update && apt-get install gitlab-ce' or 'yum update gitlab-ce')
  5. For source installations: download and install from GitLab repository for version 15.11.3 or later
  6. Verify upgrade completed successfully with 'gitlab-rake gitlab:env:info'
  7. Restart GitLab services with 'gitlab-ctl start'
  8. Confirm the vulnerability is resolved by creating a test merge request with refs/replace content
Caveat Standard GitLab upgrade risks apply - review release notes for any configuration changes required between your current version and target version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in GitLab Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA1.0 h
10.0 hours of engineering $1,750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-2181 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data