Summary
A broken authorization check in Plane allows any project member, including a Guest, to change another member's project role. An attacker may demote Administrators or Members, causing unauthorized privilege changes and loss of project control when the attacker has access to the project membership update endpoint.
A broken authorization check in Plane allows any project member, including a Guest, to change another member's project role. An attacker may demote Administrators or Members, causing unauthorized privilege changes and loss of project control when the attacker has access to the project membership update endpoint.
Affected context
The vulnerability occurs in Plane deployments where project members can invoke the ProjectMemberViewSet partial-update operation and modify member roles. The authorization logic limits assigning roles higher than the requester's role but may still permit lower or equal role assignments, including changes made by users with the Guest role.
The vulnerability occurs in Plane deployments where project members can invoke the ProjectMemberViewSet partial-update operation and modify member roles. The authorization logic limits assigning roles higher than the requester's role but may still permit lower or equal role assignments, including changes made by users with the Guest role.
Exploit preconditions
- Attack surface: Project membership role update functionality
- Required access: Membership in the affected project, including Guest-level access
- Trigger point: Partial update of another project member's role
- Why exploitation is possible: Authorization checks constrain upward privilege assignment but do not adequately restrict changes to other members or downward role changes
- Attack surface: Project membership role update functionality
- Required access: Membership in the affected project, including Guest-level access
- Trigger point: Partial update of another project member's role
- Why exploitation is possible: Authorization checks constrain upward privilege assignment but do not adequately restrict changes to other members or downward role changes
Why this happens
The underlying flaw is incomplete authorization enforcement in a role management operation. The application evaluates whether the requester can assign a role above their own but does not sufficiently verify whether the requester is permitted to modify the target member or apply lower and equal roles. This reflects CWE-269, Improper Privilege Management, because role modification authority is not consistently bound to the requester's privileges and the target resource.
The underlying flaw is incomplete authorization enforcement in a role management operation. The application evaluates whether the requester can assign a role above their own but does not sufficiently verify whether the requester is permitted to modify the target member or apply lower and equal roles. This reflects CWE-269, Improper Privilege Management, because role modification authority is not consistently bound to the requester's privileges and the target resource.
Potential impact
- A Guest may demote project Administrators or Members
- Project control and administrative capabilities may be disrupted
- Authorized users may be denied access to project management functions
- Project settings, workflows, or membership governance could be affected
- Attackers could weaken accountability by altering member privileges
- A Guest may demote project Administrators or Members
- Project control and administrative capabilities may be disrupted
- Authorized users may be denied access to project management functions
- Project settings, workflows, or membership governance could be affected
- Attackers could weaken accountability by altering member privileges
General mitigation guidance
Mitigation generally focuses on enforcing object-level and action-level
authorization for every membership role change.
Common defensive patterns include:
- Allowing role changes only to explicitly authorized project administrators or equivalent principals
- Checking both the requester's authority and the target member's current and proposed role
- Applying deny-by-default rules for Guest and other non-administrative roles
- Requiring server-side authorization independent of client-supplied role data
- Preventing users from modifying their own or other members' roles unless policy explicitly permits it
- Running authorization tests for upward, downward, equal-role, self-targeted, and cross-project changes
- Limiting privileges and separating project membership administration from ordinary project participation
Mitigation generally focuses on enforcing object-level and action-level
authorization for every membership role change.
Common defensive patterns include:
- Allowing role changes only to explicitly authorized project administrators or equivalent principals
- Checking both the requester's authority and the target member's current and proposed role
- Applying deny-by-default rules for Guest and other non-administrative roles
- Requiring server-side authorization independent of client-supplied role data
- Preventing users from modifying their own or other members' roles unless policy explicitly permits it
- Running authorization tests for upward, downward, equal-role, self-targeted, and cross-project changes
- Limiting privileges and separating project membership administration from ordinary project participation
How teams detect issues like this
Detection approaches may include:
- Static analysis and code review searches for role-update handlers that compare only role hierarchy
- Review signals where authorization is performed without validating the target object and requested action
- Policy tests covering Guest, Member, and Administrator combinations across all role transitions
- Runtime audit monitoring for unexpected demotions, especially those initiated by low-privilege accounts
- API authorization tests that verify denied responses for unauthorized project-member modifications
- Automated security review tools that identify missing object-level authorization checks
Detection approaches may include:
- Static analysis and code review searches for role-update handlers that compare only role hierarchy
- Review signals where authorization is performed without validating the target object and requested action
- Policy tests covering Guest, Member, and Administrator combinations across all role transitions
- Runtime audit monitoring for unexpected demotions, especially those initiated by low-privilege accounts
- API authorization tests that verify denied responses for unauthorized project-member modifications
- Automated security review tools that identify missing object-level authorization checks
