API Platform Core: Relation IRIs are not type-checked: a related resource can be denormalised as the wrong resource type (type confusion)

Summary The API Platform serializer's AbstractItemNormalizer does not validate the resource type returned when resolving relation IRIs, allowing type confusion where a resource of an unintended type can be silently assigned to a relation property. Impact An attacker who can submit write requests...

CVE-2026-49858

API Platform Core is a system to create hypermedia-driven REST and GraphQL APIs. In versions from 2.6.0 prior to 4.1.29, 4.2.26, and 4.3.12, a missing isCacheKeySafe gate in the JSON:API and HAL item normalizers causes a cross-user attribute leak. ApiPropertysecurity: ... is evaluated per request...

GraphQL grant on a property might be cached with different objects

Original message: I found an issue with security grants on on properties in the GraphQL ItemNormalizer: If you use something like ApiPropertysecurity: 'isgranted"PROPERTYREAD", object, property' on a member of an entity, the grant gets cached and is only evaluated once, even if the object in...