GitLabApplication
CVE-2025-12983
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 · uneditedGitLab has remediated an issue in GitLab CE/EE affecting all versions from 16.9 before 18.3.6, 18.4 before 18.4.4, and 18.5 before 18.5.2 that could have allowed an authenticated attacker to cause a denial of service condition by submitting specially crafted markdown content with nested formatting patterns.
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 confidenceGitLab's markdown rendering engine has a denial of service vulnerability where authenticated users can submit specially crafted markdown content with nested formatting patterns (e.g., deeply nested bold, italic, or link syntax). This causes excessive computational resource consumption during markdown parsing, leading to service unavailability.
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
>= 16.9.0, < 18.3.6>= 18.4.0, < 18.4.4>= 18.5.0, < 18.5.2CVSS 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
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify installed GitLab versionRun `gitlab-rake gitlab:env:info` or check the version file at `/opt/gitlab/version` ( Omnibus) or look at the GitLab admin dashboard under Help > VersionAffected if Version is 16.9.0 through 18.3.5, 18.4.0 through 18.4.3, or 18.5.0 through 18.5.1
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Compare version against CVE rangesReview the version identified in step 1 against the affected ranges: >= 16.9.0 and < 18.3.6; >= 18.4.0 and < 18.4.4; >= 18.5.0 and < 18.5.2Affected if The installed version matches any of these ranges
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Confirm markdown rendering is accessibleVerify the GitLab instance has any feature enabled where authenticated users can submit markdown content such as issues, merge requests, comments, wikis, or markdown filesAffected if Authenticated users can submit markdown (this is the default state in GitLab) and the version check in step 1 shows an affected version
You are affected if your GitLab version falls within the listed version ranges and your instance permits authenticated users to submit markdown content, which is the default configuration.
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.
dbcve · scoped18.3.618.4.418.5.2
Upgrade GitLab to version 18.3.6, 18.4.4, 18.5.2 or later. This is a standard version upgrade with no configuration changes required.
GitLab 18.5.2 (or 18.3.6 / 18.4.4 depending on your upgrade path)
- 1. Back up your GitLab instance database and repository data before proceeding
- 2. Ensure you are currently running an affected version (16.9.0 through 18.3.5, 18.4.0 through 18.4.3, or 18.5.0 through 18.5.1)
- 3. Plan maintenance window as upgrade will require service restart
- 4. For versions 16.9.x through 18.3.x: upgrade to GitLab 18.3.6 or later (but before 18.4.0)
- 5. For versions 18.4.x: upgrade to GitLab 18.4.4 or later (but before 18.5.0)
- 6. For versions 18.5.x: upgrade to GitLab 18.5.2 or later
- 7. After upgrade, verify GitLab is operational and test markdown rendering with various content
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in GitLab
Scoped from the published advisory
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-12983 — 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-2025-12983 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
- No spam, self-promotion, credentials, or personal data