CVE-2026-43886: Outline

High severity, CVSS 8.2. EPSS: 0.3% chance of exploitation in the next 30 days.

Outline is a service that allows for collaborative documentation. From 0.84.0 to 1.6.1, a logic error in OAuthInterface.validateScope() uses Array.some() to validate requested OAuth scopes, causing the function to accept the entire scope array if any single scope is valid. An attacker can smuggle the wildcard * scope by requesting scope=read *, escalating a read-only OAuth token to full unrestricted API access including write, delete, and admin operations. This vulnerability is fixed in 1.7.0.

Affected products

• Outline Outline: from 0.84.0, before 1.7.0 (fixed in 1.7.0)

Published 2026-05-11. Last modified 2026-06-17.