CVE-2026-43889: Outline

Medium severity, CVSS 6.5. EPSS: 0.4% chance of exploitation in the next 30 days.

Outline is a service that allows for collaborative documentation. Prior to 1.7.0, the shares.create API accepts both collectionId and documentId simultaneously and, when published=false, only verifies read access for each—skipping the "share" permission check. A subsequent shares.update authorizes publication using an OR policy (can share collection OR can share document), so an attacker who holds share permission on one unrelated collection can publish a share that exposes an arbitrary document they cannot legitimately share, making it publicly accessible to unauthenticated users. This vulnerability is fixed in 1.7.0.

Affected products

• Outline Outline: before 1.7.0 (fixed in 1.7.0)

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