CVE-2025-64487: Outline is vulnerable to privilege escalation vulnerability in document sharing

Severity: high (CVSS 7.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-11 · updated 2026-06-17
Weakness: CWE-269

Description

Outline is a service that allows for collaborative documentation. Prior to 1.1.0, a privilege escalation vulnerability exists in the Outline document management system due to inconsistent authorization checks between user and group membership management endpoints. This vulnerability is fixed in 1.1.0.

Affected products

outline: before 1.1.0 — fixed in 1.1.0

How to fix

Upgrade to a fixed version: outline 1.1.0. Check the vendor advisory for mitigations.

References

https://github.com/outline/outline/releases/tag/v1.1.0
https://github.com/outline/outline/security/advisories/GHSA-c8xf-3j86-7686

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