GitLabApplication
CVE-2026-6335
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 18.11 before 18.11.3 that under certain conditions could have allowed an authenticated user to execute arbitrary code in another user's browser session due to improper sanitization.
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 confidenceThis is a stored Cross-Site Scripting (XSS) vulnerability in GitLab CE/EE affecting versions 18.11 before 18.11.3. An authenticated user could inject malicious JavaScript code through improper input sanitization, which would then execute in another user's browser session when viewed, potentially allowing session hijacking or actions on behalf of the victim.
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
>= 18.11.0, < 18.11.3CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/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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Check installed GitLab versionRun `sudo gitlab-rake gitlab:version` or navigate to Help > Version in the GitLab web interfaceAffected if Version shows 18.11.0, 18.11.1, or 18.11.2 (any version >= 18.11.0 but < 18.11.3)
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Verify version against affected rangeCompare the installed version number to the vulnerable range: 18.11.0 through 18.11.2 inclusiveAffected if Installed version is 18.11.0, 18.11.1, or 18.11.2
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Confirm GitLab editionDetermine if running Community Edition (CE) or Enterprise Edition (EE) - both share the same vulnerable code baseAffected if Either GitLab CE or EE is running at a version within the affected range
Your environment is affected if GitLab CE or EE version is 18.11.0, 18.11.1, or 18.11.2 (any version from 18.11.0 up to but not including 18.11.3)
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 · scoped18.11.3
Upgrade GitLab to version 18.11.3 or later. If immediate upgrading is not possible, identify and neutralize the vulnerable input field through WAF rules while planning the upgrade.
18.11.3
- Backup your GitLab instance data and database before proceeding with the upgrade
- Confirm current GitLab version is >= 18.11.0 and < 18.11.3 by navigating to Admin Area > Overview > Dashboard or running `gitlab-rake gitlab:env:info`
- Update GitLab to version 18.11.3 using your installation method (omnibus package, source, or Docker)
- After upgrade completes, run `sudo gitlab-rake gitlab:migrations:status` to ensure all migrations are up to date
- Verify the upgrade was successful by checking the GitLab version at Admin Area > Overview > Dashboard
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in GitLab
Scoped from the published advisory
- Consultation4.0 h
- Implementation4.0 h
- Testing6.0 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 $4,448.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-6335 — 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-2026-6335 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