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GitLabApplication

CVE-2023-3364

HIGH · 7.5 CVSS v3.1 Published 2023-08-02
Fix available
A fix is available. Upgrade to 16.0.8 / 16.1.3 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 8.14 before 16.0.8, all versions starting from 16.1 before 16.1.3, all versions starting from 16.2 before 16.2.2. A Regular Expression Denial of Service was possible via sending crafted payloads which use AutolinkFilter 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 exists in GitLab's preview_markdown endpoint via the AutolinkFilter component. Attackers can send crafted regex payloads that cause excessive backtracking, leading to CPU exhaustion and service unavailability.

MitigationUpgrade GitLab to version 16.0.8, 16.1.3, 16.2.2 or later to patch the vulnerable regex patterns in the AutolinkFilter.

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:>= 8.14, < 16.0.8>= 16.1, < 16.1.3>= 16.2, < 16.2.2

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
    Run `sudo gitlab-rake gitlab:env:info` or check the GitLab admin panel under Help > Version to find the exact version number
    Affected if The version falls within any of these ranges: >= 8.14 and < 16.0.8, OR >= 16.1 and < 16.1.3, OR >= 16.2 and < 16.2.2
  2. Verify preview_markdown endpoint is accessible
    Check if the `/api/v4/markdown` or `/api/v4/markdown/preview` endpoint responds to requests. This is typically enabled by default in GitLab installations.
    Affected if The endpoint returns a valid response, indicating it is active and reachable
  3. Confirm AutolinkFilter module is loaded
    Review GitLab configuration files (gitlab.yml or gitlab.rb) or check the Rails console output for markdown processing modules. The AutolinkFilter is part of the standard markdown processing pipeline.
    Affected if The markdown preview functionality uses the standard GitLab markdown pipeline which includes AutolinkFilter

If your GitLab version is within the affected ranges AND the preview_markdown endpoint is accessible, your environment is vulnerable to CVE-2023-3364 ReDoS attacks via crafted regex payloads to the AutolinkFilter component.

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 16.0.8 / 16.1.3 / 16.2.2 or later
Fixed in 16.0.816.1.316.2.2
Interim mitigation

Upgrade GitLab to version 16.0.8, 16.1.3, 16.2.2 or later to patch the vulnerable regex patterns in the AutolinkFilter.

Recommended fix High confidence

16.0.8, 16.1.3, 16.2.2 or later (recommended: latest 16.x stable release)

  1. 1. Determine your current GitLab installation method (Omnibus, source, or Docker)
  2. 2. Back up your GitLab data and configuration before upgrading
  3. 3. For Omnibus installations: Run 'sudo apt-get update' and 'sudo apt-get install gitlab-ce' (or 'gitlab-ee') to upgrade to the latest patched version
  4. 4. For Docker installations: Pull and run the latest patched image (16.2.2 or later, e.g., 'docker pull gitlab/gitlab-ee:16.2.2' or later)
  5. 5. For source installations: Stop GitLab services, download the new version from gitlab.com, and follow the upgrade documentation
  6. 6. After upgrade, verify GitLab is running and the preview_markdown endpoint functions correctly
  7. 7. Monitor for any regressions or issues post-upgrade
Caveat Review GitLab release notes for your upgrade path as major version jumps may require intermediate upgrades and could include breaking changes

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
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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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-2023-3364 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