CVE-2026-1090
Received Received - Intake
JavaScript Injection via Markdown Placeholder in GitLab CE/EE

Publication date: 2026-03-11

Last updated on: 2026-03-13

Assigner: GitLab Inc.

Description
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 10.6 before 18.7.6, 18.8 before 18.8.6, and 18.9 before 18.9.2 that could have allowed an authenticated user, when the `markdown_placeholders` feature flag was enabled, to inject JavaScript in a browser due to improper sanitization of placeholder content in markdown processing.
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Meta Information
Published
2026-03-11
Last Modified
2026-03-13
Generated
2026-06-16
AI Q&A
2026-03-11
EPSS Evaluated
2026-06-15
NVD
CVE-2026-1090
EUVD
EUVD-2026-11180
Affected Vendors & Products
Showing 6 associated CPEs
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
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KEV
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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.
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Executive Summary

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.

Impact Analysis

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.

Compliance Impact

I don't know

Detection Guidance

I don't know

Mitigation Strategies

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.

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