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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-104970
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-05 17:17:12 UTC
Updated2026-10-06 15:17:13 UTC
DescriptionPlane 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.

Risk And Classification

Primary CVSS: v3.1 8.1 HIGH from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.002650000 probability, percentile 0.167960000 (date 2026-10-06)

Problem Types: CWE-362 | CWE-362 CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.1HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED8.1HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Makeplane Plane affected < 1.4.0 Not specified

References

ReferenceSourceLinkTags
github.com/makeplane/plane/releases/tag/v1.4.0 [email protected] github.com
github.com/makeplane/plane/security/advisories/GHSA-p548-28jp-wr4p [email protected] github.com
github.com/makeplane/plane/pull/9332 [email protected] github.com
github.com/makeplane/plane/commit/7fbf14a6cb494bbf5866e2b293b28a6d8a7e52c3 [email protected] github.com
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