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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-03-11

Last Modified

2026-03-13

Generated

2026-07-06

AI Q&A

2026-03-11

EPSS Evaluated

2026-07-05

NVD

CVE-2026-1090

EUVD

EUVD-2026-11180

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

KEV

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

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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