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GitLabApplication

CVE-2023-3424

HIGH · 7.5 CVSS v3.1 Published 2023-07-13
Fix available
A fix is available. Upgrade to 15.11.10 / 16.0.6 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges 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 CE/EE affecting all versions starting from 10.3 before 15.11.10, all versions starting from 16.0 before 16.0.6, all versions starting from 16.1 before 16.1.1. A Regular Expression Denial of Service was possible via sending crafted payloads to the preview_markdown endpoint.

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 Regular Expression Denial of Service (ReDoS) vulnerability in GitLab's preview_markdown endpoint allows attackers to send crafted regex payloads that cause catastrophic backtracking, potentially hanging or crashing the GitLab service.

MitigationUpgrade GitLab to version 15.11.10, 16.0.6, 16.1.1 or later. Consider rate-limiting or temporarily disabling the preview_markdown endpoint as a defensive measure while planning the upgrade.

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:>= 10.3.0, < 15.11.10>= 16.0.0, < 16.0.6>= 16.1.0, < 16.1.1

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
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 checks

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

  1. Determine installed GitLab version
    Log into the GitLab admin area and navigate to the Help page or use command 'gitlab-rake gitlab:env:info' on the server to retrieve the exact version number
    Affected if The version falls within any of these ranges: >= 10.3.0 and < 15.11.10, OR >= 16.0.0 and < 16.0.6, OR >= 16.1.0 and < 16.1.1
  2. Verify preview_markdown endpoint is accessible
    Check if the /api/v4/markdown_preview endpoint is available by attempting a request to https://your-gitlab-instance/api/v4/markdown_preview or reviewing API documentation settings in the Admin area under Settings > API
    Affected if The endpoint responds to requests (returns 200 or 401/403 rather than 404)
  3. Confirm endpoint does not have rate limiting
    Review GitLab settings in Admin area under Settings > Network > Rate Limiting to see if preview_markdown endpoint is explicitly exempted or has no throttling applied
    Affected if Rate limiting is disabled or not configured for this endpoint, making it vulnerable to abuse

You are affected if your GitLab version is one of the vulnerable versions listed AND the preview_markdown API endpoint is accessible and lacks sufficient rate limiting protection.

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 15.11.10 / 16.0.6 / 16.1.1 or later
Fixed in 15.11.1016.0.616.1.1
Interim mitigation

Upgrade GitLab to version 15.11.10, 16.0.6, 16.1.1 or later. Consider rate-limiting or temporarily disabling the preview_markdown endpoint as a defensive measure while planning the upgrade.

Recommended fix High confidence

15.11.10 (or latest 15.11.x), 16.0.6 (or latest 16.0.x), or 16.1.1 (or latest 16.1.x/16.2+)

  1. Backup your GitLab instance database and repositories before starting the upgrade
  2. Schedule a maintenance window as the upgrade may require downtime
  3. Check your current GitLab version in Admin Area > Settings > Metrics and profiling > Version
  4. For GitLab 15.x: Upgrade to version 15.11.10 or later (recommended: latest 15.11.x stable)
  5. For GitLab 16.0.x: Upgrade to version 16.0.6 or later (recommended: latest 16.0.x stable)
  6. For GitLab 16.1.x: Upgrade to version 16.1.1 or later (recommended: latest 16.1.x stable or 16.2+)
  7. Run sudo gitlab-ctl reconfigure after upgrade completes
  8. Verify the upgrade was successful by checking the version in Admin Area
Caveat Standard GitLab upgrade precautions apply - review release notes for between-version migrations

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-2023-3424 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