Unleash: Clone-feature lets a user copy a feature from a project they cannot read

Summary

The clone-feature endpoint supports copying features across projects, but it does not verify that the caller can access the source project. A user with create permissions in one project can clone a feature from another project they cannot read and then inspect the copied configuration.

This vulnerability cannot be confirmed without Enterprise access. Report is based on a circumstantial evidence in the open-source repository.

Details

src/lib/features/feature-toggle/feature-toggle-service.ts implements cloneFeatureToggle. This operation needs authorization for both sides: permission to read/copy the source feature and permission to create the destination feature.

The clone path validates permissions against the destination project, but not against the source project that owns featureName. Because feature names are globally unique, a caller can reference a feature outside projects they can access.

PoC

1. Create or identify two projects: P1 with a private or restricted feature named secret-feature, and P2 where the attacker has clone/create permissions.
2. Authenticate as the attacker.
3. Send:

POST /api/admin/projects/P2/features/secret-feature/clone
Content-Type: application/json

{ "name": "secret-feature-copy" }

4. Open P2 and inspect secret-feature-copy. Verify if strategy parameters, constraints, variants, and variant payloads from the source feature have been copied.

Impact

Users with permissions on one project can disclose feature configuration from another project if they know or guess the source feature name. Feature names could be available in more public applications that have a common SDK access to multiple projects.