CVE-2026-1090
JavaScript Injection via Markdown Placeholder in GitLab CE/EE
Publication date: 2026-03-11
Last updated on: 2026-03-13
Assigner: GitLab Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| gitlab | gitlab | From 18.8.0 (inc) to 18.8.6 (exc) |
| gitlab | gitlab | From 18.9.0 (inc) to 18.9.2 (exc) |
| gitlab | gitlab | From 18.8.0 (inc) to 18.8.6 (exc) |
| gitlab | gitlab | From 18.9.0 (inc) to 18.9.2 (exc) |
| gitlab | gitlab | From 10.6.0 (inc) to 18.7.6 (exc) |
| gitlab | gitlab | From 10.6.0 (inc) to 18.7.6 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-79 | The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability in GitLab CE/EE affects versions from 10.6 before 18.7.6, 18.8 before 18.8.6, and 18.9 before 18.9.2. It occurs when the 'markdown_placeholders' feature flag is enabled, allowing an authenticated user to inject JavaScript into a browser. This happens due to improper sanitization of placeholder content during markdown processing.
How can this vulnerability impact me? :
The vulnerability can lead to cross-site scripting (XSS) attacks, where an authenticated user can inject malicious JavaScript code. This can compromise the confidentiality and integrity of data, potentially allowing attackers to steal sensitive information, hijack user sessions, or perform actions on behalf of other users.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
I don't know
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, you should upgrade GitLab CE/EE to a fixed version. Specifically, update to version 18.7.6 or later if you are using 18.7, 18.8.6 or later if you are using 18.8, or 18.9.2 or later if you are using 18.9.
Additionally, if the `markdown_placeholders` feature flag is enabled, consider disabling it until you have applied the update, as the vulnerability is related to improper sanitization when this feature is active.