CVE-2026-104970 — Plane: InstanceAdminSignUpEndpoint TOCTOU race allows two concurrent unauthenticated callers to both bootstrap as Plane instance admins
Plane is an open-source project management tool. From 0.13 until 1.4.0, InstanceAdminSignUpEndpoint in apps/api/plane/license/api/views/admin.py:89-117, 173-229 uses InstanceAdm…
Published: 2026-10-05 · CVSS: 8.1 · CVSS 3.1
Plane is an open-source project management tool. From 0.13 until 1.4.0, InstanceAdminSignUpEndpoint in apps/api/plane/license/api/views/admin.py:89-117, 173-229 uses InstanceAdmin.objects.first() for the first-admin check and performs account creation without an atomic transaction, row lock, uniqueness guard, or advisory lock. Two concurrent unauthenticated requests with different email addresses can both observe that no instance administrator exists, create separate User and InstanceAdmin rows, and receive sessions with instance-admin authority. This allows an attacker to share unrestricted instance administration with the legitimate operator. This issue is fixed in 1.4.0.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7