Plane: Pre-auth workspace invitation hijack via email-squat and self-served invitation token leak in Plane

{
  "id": "435b5266f9166b90a59481afb2ce40515929668e8ce0338727b69734478fbc55",
  "url": "https://osv.dev/vulnerability/CVE-2026-105639",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "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 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.",
    "evidence": "osv:CVE-2026-105639",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-105639",
      "aliases": [
        "CVE-2026-105639",
        "GHSA-4vj8-p63v-8p24"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/makeplane/plane",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "917b23a6c16d93fc00cef67900eff2755e8b13f7"
                },
                {
                  "fixed": "6220ba990b2276a1a1979d1d5df68f650b8b47ad"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "1.4.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "6220ba990b2276a1a1979d1d5df68f650b8b47ad"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "917b23a6c16d93fc00cef67900eff2755e8b13f7"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v1.4.0"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.3.1",
            "v1.3.0",
            "v1.2.3",
            "v1.2.2",
            "v1.2.1",
            "v1.2.0",
            "v1.1.0",
            "v1.0.0",
            "v0.28.0",
            "v0.27.1",
            "v0.27.0",
            "v0.26.1",
            "v0.26.0",
            "v0.25.3",
            "v0.25.2",
            "v0.25.1",
            "v0.25.0",
            "v0.24.0",
            "v0.23.1",
            "v0.23.0",
            "v0.22-dev",
            "v0.21-dev",
            "v0.20-dev",
            "v0.19-dev",
            "v0.18-dev",
            "v0.17-dev",
            "v0.16-dev",
            "v0.15.4-dev",
            "v0.15.3-hotfix",
            "v0.15.2-dev",
            "v0.15.1-dev",
            "v0.15-dev",
            "v0.14.2-dev",
            "v0.14.1-dev",
            "v0.14-dev",
            "v0.13.2-dev",
            "v0.13.1-dev",
            "v0.13-dev",
            "v0.12.2-dev",
            "v0.12.1-dev",
            "v0.12-dev",
            "v0.11-dev",
            "v0.10-dev",
            "v0.9-dev",
            "v0.8-dev",
            "v0.7.1-dev",
            "v0.7-dev",
            "v0.6-dev",
            "v0.5-dev",
            "v0.4-dev",
            "v0.3.1-dev",
            "v0.1-dev"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-105639.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:39.403489676Z",
      "provider": "osv",
      "references": [
        "https://github.com/makeplane/plane/releases/tag/v1.4.0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/105xxx/CVE-2026-105639.json",
        "https://github.com/makeplane/plane/security/advisories/GHSA-4vj8-p63v-8p24",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-105639",
        "https://github.com/makeplane/plane/commit/6220ba990b2276a1a1979d1d5df68f650b8b47ad",
        "https://github.com/makeplane/plane/pull/9297"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-200",
          "CWE-287",
          "CWE-639"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/105xxx/CVE-2026-105639.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-105639",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 506633,
  "published_at": "2026-10-05T18:10:35.787+00:00"
}