Vulnerability · Published May 11, 2026 · Assigned by GitHub_M

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

High 7.3

In plain English

A high-severity cross-site scripting in outline from outline. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities).

Severity (CVSS 3.1)7.3High

Exploit odds (30 days)0.2%top 84.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
outline	outline	>= 0.84.0, < 1.7.0

Weakness: CWE-79 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N

References

https://github.com/outline/outline/security/advisories/GHSA-rqrg-f3qc-xvgh x_refsource_CONFIRM