Unleash is an open-source feature management platform. Prior to 8.0.3, POST /api/admin/projects/:projectId/features/:featureName/environments/:environment/strategies/set-sort-order passes attacker-controlled strategy IDs to unprotectedUpdateStrategiesSortOrder and updateSortOrder without verifying that the IDs belong to the project, feature, and environment authorized by the URL. In a multi-project Pro or Enterprise deployment, an authenticated user with UPDATE_FEATURE_STRATEGY in one project who knows another project's strategy IDs can reorder those strategies, changing feature evaluation precedence while the operation is attributed to the attacker's URL context rather than the affected project. The single-project OSS edition lacks the cross-project dimension, although the missing context binding still permits unauthorized reordering across features or environments in the default project. The endpoint changes only sort_order and does not modify strategy parameters, constraints, or segments. This issue is fixed in version 8.0.3.

Affected: npm: unleash-server

## Summary

Unleash scopes write permissions per project and per environment: a user with the `UPDATE_FEATURE_STRATEGY` permission on project `A` is supposed to be able to mutate activation strategies only within project `A`. The endpoint `POST /api/admin/projects/:projectId/features/:featureName/environments/:environment/strategies/set-sort-order` violates this. The RBAC middleware authorizes the request against the `:projectId` taken from the URL, but the handler then writes the strategy IDs supplied in the request *body* directly to the database by primary key, **without ever verifying that those strategy IDs actually belong to the URL's project / feature / environment**. A low-privilege member of any one project can therefore reorder the activation strategies of features in *any other project and environment* — including projects they have no role on at all — by putting their own project in the URL (to satisfy RBAC) and the victim project's strategy IDs in the body.

The sibling write paths in the same service (`updateStrategy`, `patchStrategy`, `deleteStrategy`) all call `validateUpdatedProperties()`, which rejects a strategy whose stored `projectId`/`featureName` does not match the URL context. The `set-sort-order` handler is the one sibling that omits this check — an asymmetric, incomplete enforcement. Activation-strategy ordering is security-relevant: the first matching strategy determines a flag's rollout/variant outcome, so an attacker can flip which strategy "wins…