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Vulnerability · Published Oct 5, 2026 · Assigned by GitHub_M

CVE-2026-104970Plane: InstanceAdminSignUpEndpoint TOCTOU race allows two concurrent unauthenticated callers to both bootstrap as Plane instance admins

High 8.1

In plain English

A high-severity race condition in plane from makeplane. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 18% of all known vulnerabilities).

Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.3%top 81.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
makeplane plane < 1.4.0

Weakness: CWE-362 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References