What’s Vulnerable › Vulnerabilities

CVE-2026-43889: Outline: Unauthorized Document Publication via Mixed collectionId+documentId Share

• Severity: medium (CVSS 6.5 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: 2026-05-11 · updated 2026-06-17
• Weakness: CWE-863

Description

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: before 1.7.0

References

• https://github.com/outline/outline/security/advisories/GHSA-rg4j-pmch-w6pm
• https://github.com/outline/outline/security/advisories/GHSA-rg4j-pmch-w6pm

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