Plane is an open-source project management tool. Prior to 1.4.0, a Project Member with role 15 can send a PATCH request to the project-member update endpoint at /api/workspaces/{workspace_slug}/projects/{project_id}/members/{member_pk}/ to change another user's project role. The role-update logic blocks only a new role higher than the requester's role, so assigning the equal Member role bypasses the insufficient validation and promotes a Project Guest with role 5 to Member without Project Admin approval. This unauthorized promotion grants the guest the additional project capabilities associated with the Member role and allows a regular member to bypass project governance controls. This issue is fixed in 1.4.0.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-269",
"CWE-285"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/104xxx/CVE-2026-104955.json"
}