CVE-2026-43887
Received Received - Intake
Stored XSS in Outline Comment Mentions

Publication date: 2026-05-11

Last updated on: 2026-05-11

Assigner: GitHub, Inc.

Description
Outline is a service that allows for collaborative documentation. From 0.84.0 to 1.6.1, the Outline comment section permits users to mention other users; however, the backend does not validate or sanitize the href attribute associated with these mentions. As a result, potentially dangerous protocols (e.g., javascript:) are not filtered, introducing a risk of client-side code execution. This vulnerability is fixed in 1.7.0.
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Meta Information
Published
2026-05-11
Last Modified
2026-05-11
Generated
2026-06-21
AI Q&A
2026-05-12
EPSS Evaluated
2026-06-20
NVD
CVE-2026-43887
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
outline outline 1.7.0
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 exists in the Outline service versions from 0.84.0 to 1.6.1, specifically in the comment section where users can mention other users. The backend does not properly validate or sanitize the href attribute in these mentions, allowing potentially dangerous protocols such as "javascript:" to be included. This flaw can lead to client-side code execution, meaning that malicious scripts could run in the context of a user's browser.

Impact Analysis

The vulnerability can lead to client-side code execution, which may allow attackers to execute malicious scripts in the browsers of users interacting with the Outline service. This can result in unauthorized actions such as stealing sensitive information, hijacking user sessions, or performing actions on behalf of the user without their consent.

Mitigation Strategies

To mitigate this vulnerability, upgrade the Outline service to version 1.7.0 or later, where the issue with unsanitized href attributes in user mentions has been fixed.

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0/70
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