High 8.1Published Oct 5, 2026

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

Updated under an hour ago (2026-10-19 08:23 UTC)

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It affects makeplane plane. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.27%, higher than 17% of scored CVEs.

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Exploited in the last 30 days

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.

CVSS: 8.1 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE): CWE-362
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.27% (percentile 17)
Assigned by: GitHub_M
NVD analysis: Deferred
Record last updated: Oct 6, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

makeplane plane makeplane:plane (from the name)	before 1.4.0	CNA record

References

https://github.com/makeplane/plane/security/advisories/GHSA-p548-28jp-wr4px-refsource-confirm
https://github.com/makeplane/plane/pull/9332x-refsource-misc
https://github.com/makeplane/plane/commit/7fbf14a6cb494bbf5866e2b293b28a6d8a7e52c3x-refsource-misc
https://github.com/makeplane/plane/releases/tag/v1.4.0x-refsource-misc

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.