CVE-2026-43887 HIGH

CVE-2026-43887: Outline: Stored XSS via Comment Mentions

Vendor Outline
Product outline
Weakness CWE-79 · XSS
Published May 11, 2026
Last update May 15, 2026

CVSS base score

7.3/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction Required
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

May 11, 2026 CVE published
May 15, 2026 Record updated