---
id: CVE-2026-105639
title: >-
  Plane: Pre-auth workspace invitation hijack via email-squat and self-served
  invitation token leak in Plane
summary: >-
  Plane is an open-source project management tool. Prior to 1.4.0, Plane's
  signup flow creates a logged-in User row for any submitted email without an
  out-of-band ownership check, while User.email is unique=True. The
  authenticated user can…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-200
  - CWE-287
  - CWE-639
vendor: makeplane
product: plane
affected:
  - plane < 1.4.0
published: '2026-10-05'
updated: '2026-10-05'
sourceUpdated: '2026-10-05T18:10:35.787Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-105639'
references:
  - url: 'https://github.com/makeplane/plane/security/advisories/GHSA-4vj8-p63v-8p24'
    label: 'https://github.com/makeplane/plane/security/advisories/GHSA-4vj8-p63v-8p24'
  - url: 'https://github.com/makeplane/plane/pull/9297'
    label: 'https://github.com/makeplane/plane/pull/9297'
  - url: >-
      https://github.com/makeplane/plane/commit/6220ba990b2276a1a1979d1d5df68f650b8b47ad
    label: >-
      https://github.com/makeplane/plane/commit/6220ba990b2276a1a1979d1d5df68f650b8b47ad
  - url: 'https://github.com/makeplane/plane/releases/tag/v1.4.0'
    label: 'https://github.com/makeplane/plane/releases/tag/v1.4.0'
tags:
  - cve.org
ingestedAt: '2026-10-05T18:29:11.209Z'
---

## Overview

Plane is an open-source project management tool. Prior to 1.4.0, Plane's signup flow creates a logged-in User row for any submitted email without an out-of-band ownership check, while User.email is unique=True. The authenticated user can call GET /api/users/me/workspaces/invitations/, which returns each WorkspaceMemberInvite whose email matches request.user.email. WorkSpaceMemberInviteSerializer uses fields = "all", exposing the token that protects the invitation join endpoint. An unauthenticated attacker who knows a target's email can register an account using that address, enumerate pending invitations, and accept an invitation as the target, joining a workspace at the invited role. The term pre-auth describes the attacker's initial state: the attacker has no credential before signup, while the enumeration and join requests use the session created by that signup. This issue is fixed in 1.4.0.

## Affected

- `plane < 1.4.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.