GitLabApplication
CVE-2019-15586
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 · uneditedA XSS exists in Gitlab CE/EE < 12.1.10 in the Mermaid plugin.
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 · moderate confidenceThis is a stored Cross-Site Scripting (XSS) vulnerability in GitLab's Mermaid diagram rendering plugin. Attackers can inject malicious JavaScript code through specially crafted Mermaid diagram definitions that execute when other users view the content.
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
>= 12.1.0, < 12.1.10CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/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 checksWork through these to decide whether this CVE applies to you.
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Determine your GitLab installation methodIdentify if GitLab is installed via Omnibus package (common), source, or a cloud-hosted instance. For Omnibus, check /opt/gitlab/version; for source installations, check the version file in the GitLab directory.Affected if Any installation method where the version cannot be verified as 12.1.10 or later.
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Find the installed GitLab versionRun command: gitlab-rake gitlab:env:info or check /opt/gitlab/version for Omnibus installations. For source, check the VERSION file in the GitLab root directory.Affected if The displayed version is greater than or equal to 12.1.0 but less than 12.1.10.
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Confirm Mermaid diagram rendering is in useSearch Git repositories, wikis, issues, merge requests, or markdown files for Mermaid syntax: ```mermaid ... ``` or mermaid code blocks. Check if users are creating diagrams using the mermaid keyword in markdown content.Affected if Mermaid diagrams are rendered in any accessible content areas such as issues, merge requests, wikis, or README files.
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Identify accessible user-generated contentReview public and internal projects, wikis, and issues for any Mermaid diagram definitions that may have been submitted before patching. Use GitLab search or API to query for mermaid keyword in project content.Affected if Content containing Mermaid syntax exists and is accessible to other users who would view the rendered diagram.
You are affected if your GitLab version is 12.1.0 through 12.1.9 and users can create or view Mermaid diagram content in issues, wikis, merge requests, or markdown files.
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 data12.1.10
Upgrade GitLab CE/EE to version 12.1.10 or later to patch the vulnerability in the Mermaid plugin.
Fix this in GitLab
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,224.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-15586 — 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-2019-15586 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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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.
- 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