CVE-2026-104969: Plane: Cross-Tenant Cycle Issue Hijack via IDOR

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-05 · updated 2026-10-05
Weakness: CWE-639

Description

Plane is an open-source project management tool. Prior to 1.4.0, the cycle-issues endpoint accepts issue UUIDs in the request body without validating that they belong to the caller's workspace. An authenticated user can add issues from any workspace to a cycle they control. If a victim issue is already assigned to a cycle, the operation removes it from the victim's cycle, causing a destructive cross-tenant write. This issue is fixed in 1.4.0.

Affected products

makeplane plane: before 1.4.0

References

https://github.com/makeplane/plane/commit/81d9873d7f1cf1d1252ed53c12dd33696be73a89
https://github.com/makeplane/plane/pull/9269
https://github.com/makeplane/plane/releases/tag/v1.4.0
https://github.com/makeplane/plane/security/advisories/GHSA-22g9-9xfv-q3fr
https://github.com/makeplane/plane/security/advisories/GHSA-22g9-9xfv-q3fr

Get alerted when CVE-2026-104969 or the next vulnerability affects your stack