CVE-2026-76909

Unleash prior to 8.0.3 contains five authorization vulnerabilities in the admin API that allow authenticated users to modify segment assignments, disclose cross-project variant, strategy, and environment information, and modify tags across projects without proper permissions.

Unleash prior to 8.0.3, in the POST /api/admin/projects/:projectId/features/:featureName/environments/:environment/strategies/set-sort-order endpoint, passes attacker-controlled strategy IDs to unprotected updateStrategiesSortOrder 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.

Unleash prior to 8.0.3, in cloneFeatureToggle and POST /api/admin/projects/:projectId/features/:featureName/clone, authorizes creation in the destination project but does not verify access to the source project. Because feature names are globally unique, a user with create or clone permission in one project who knows or guesses another project's feature name can copy that feature into the authorized project and inspect its strategy parameters, constraints, variants, and variant payloads. This issue is fixed in version 8.0.3.

In Unleash before 8.0.3, FeatureEventFormatterMd.format assigns Mustache.escape to an identity function before rendering action and path templates. This disables escaping for subsequent Mustache.render calls in email-service.ts, webhook.ts, datadog.ts, and new-relic.ts. An editor-level user can place Slack or Microsoft Teams link syntax in an unrestricted username, trigger a feature event, and inject an attacker-labeled link into a trusted outbound notification channel, while other Mustache sinks remain unescaped until restart.

Unleash is an open-source feature management platform. Prior to 7.5.2, 7.6.5, and 8.0.2, the shared OpenAPI validation error path in src/lib/error/bad-data-error.ts passes a raw request value from lodash.get to JSON.stringify in genericErrorMessage and fromOpenAPIValidationErrors without guarding stack exhaustion. An unauthenticated attacker can send a roughly 10 KB JSON value nested thousands of levels deep to POST /edge/validate, POST /edge/issue-token, or another OpenAPI-validated endpoint, causing RangeError: Maximum call stack size exceeded in openAPIValidationMiddleware and terminating the Node process because no uncaughtException handler recovers it. Replaying the request can sustain a complete service outage. This issue is fixed in versions 7.5.2, 7.6.5, and 8.0.2.

In Unleash before 7.5.2, 7.6.5, and 8.0.2, the addon and integration subsystem passes the operator-controlled parameters.url value from webhook.ts and the Slack, Microsoft Teams, Datadog, and New Relic integrations to Addon.fetchRetry without restricting loopback, link-local, private, or cloud metadata addresses. An authenticated actor with root CREATE_ADDON or UPDATE_ADDON permission can cause the server to send requests from inside its network boundary, use integration event status as a blind probing oracle, forward Authorization, customHeaders, or DD-API-KEY values to an attacker-observed host, and deliver the feature-event JSON body to internal services.