CVE-2025-58351 Outline's Local File Storage Feature can Cause CSP Bypass

Medium 6.8 Published 3 Sep 2025 Updated 3 Sep 2025

Attackers can execute scripts in other users' contexts by uploading malicious files when local storage is enabled on the same domain.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Over the internet
Victim action needed: A user has to click or open something
Fix: None listed

What is CVE-2025-58351?

CVE-2025-58351 is a medium-severity cross-site scripting vulnerability in outline, published on 3 Sep 2025. Any signed-in user can exploit it over the network, and only if a user opens a file or follows a link.

Official description

Outline is a service that allows for collaborative documentation. In versions 0.72.0 through 0.83.0, Outline introduced a feature which facilitates local file system storage capabilities as an optional file storage strategy. This feature allowed a CSP bypass as well as a ContentType bypass that might facilitate further attacks. In the case of self-hosting and using Outline FILE_STORAGE=local on the same domain as the Outline application, a malicious payload can be uploaded as a file attachment and bypass those CSP restrictions, allowing script execution within the context of another user. This is fixed in version 0.84.0.

Weakness: CWE-79

Which versions are affected by CVE-2025-58351?

It affects 1 product.

Products include Getoutline Outline.

How do I fix CVE-2025-58351?

No fix has been published for CVE-2025-58351 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2025-58351 being exploited?

There is no known exploitation of CVE-2025-58351 in the wild and no public exploit code.

Sources

Also known as GHSA-gcj7-c9jv-fhgf.