Race condition in Plane lets attackers create extra instance admins
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
Plane from 0.13 before 1.4.0 has a race condition (CWE-362) in InstanceAdminSignUpEndpoint. The endpoint checks for an existing instance administrator without locking or a uniqueness guard, so two concurrent unauthenticated sign-up requests with different email addresses can both pass the check. An unauthenticated attacker can thereby obtain instance-admin sessions alongside the legitimate operator.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
Description from the CNA
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
Upgrade makeplane Plane to 1.4.0, which fixes this issue.
Written with Claude Haiku 5.5 from the sources below · 2026-10-29
- Fix · CNA plane (makeplane) Fixed in 1.4.0
Timeline
- 2026-10-05 Threatist record created from CVE-2026-104970
- 2026-10-06 CISA SSVC decision points changed
- 2026-10-06 Priority changed: MEDIUM → LOW
References
More makeplane vulnerabilities
- TI-2026-67866 Hardcoded secret keys in Plane community deployments CVSS 3.1CRITICAL 9.8
- TI-2026-67865 Account takeover in Plane via unverified OAuth email matching CVSS 3.1CRITICAL 9.1
- TI-2026-67863 Plane magic-code login lacks rate limiting, allowing OTP brute force CVSS 3.1CRITICAL 9.1
- TI-2024-32097 Plane allows server side request forgery via /_next/image endpoint CVSS 3.1CRITICAL 9.3
- TI-2026-67862 Cross-project asset hijacking in Plane allows file takeover CVSS 3.1CRITICAL 9.6
- TI-2026-67861 Server-side request forgery in Plane webhook delivery via redirects CVSS 3.1CRITICAL 9.9
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences