What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.1 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 2026-10-06
• Weakness: CWE-362

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

• makeplane plane: before 1.4.0

References

• https://github.com/makeplane/plane/commit/7fbf14a6cb494bbf5866e2b293b28a6d8a7e52c3
• https://github.com/makeplane/plane/pull/9332
• https://github.com/makeplane/plane/releases/tag/v1.4.0
• https://github.com/makeplane/plane/security/advisories/GHSA-p548-28jp-wr4p

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