CVE-2025-58351: outline XSS — Fix

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.

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CVSS v3.1 Score

6.8

MEDIUM

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

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
getoutline	outline	0.72.0 — 0.84.0

References

Advisories & Patches

https://github.com/outline/outline/commit/18bc93c9c207329244c6909606a2393e863892a3 https://github.com/outline/outline/security/advisories/GHSA-gcj7-c9jv-fhgf

Other References

https://github.com/outline/outline/releases/tag/v0.84.0

Frequently Asked Questions

What is CVE-2025-58351? +

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. It has a CVSS v3.1 base score of 6.8 (MEDIUM).

How severe is CVE-2025-58351? +

CVE-2025-58351 has a CVSS v3.1 score of 6.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-58351? +

CVE-2025-58351 affects products from getoutline, specifically: outline. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-58351? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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