Threat database

## 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 (POST/PUT/PATCH) to an API Platform endpoint with writable relations can supply a relation IRI pointing to a resource of a different type than the relation's declared class. Because `getResourceFromIri()` does not pass an `$operation` to `IriConverter::getResourceFromIri()`, the `is_a` type guard at `IriConverter.php:86` is skipped. For untyped relation properties (legacy `@var`-only style), the wrong-typed object is silently assigned, corrupting invariants and potentially feeding downstream logic that assumes the declared type (CWE-843). For typed properties (modern PHP 8.x), the substitution is blocked by Symfony's PropertyAccessor with an `InvalidTypeException`. ## Affected versions - `api-platform/core` `< 4.1.30` - `api-platform/core` `>= 4.2.0, < 4.2.26` - `api-platform/core` `>= 4.3.0, < 4.3.12` Older major series (`2.x`, `3.x`) ship the same vulnerable code path and are end-of-life; no fix is planned. ## Patched versions - `4.1.30` - `4.2.26` - `4.3.12` ## Fix An `is_a` guard is added inside `AbstractItemNormalizer::getResourceFromIri()` (and the equivalent inline call sites on 4.1) so that a mismatched IRI throws `InvalidArgumentException`, mirroring the operation-aware check the `IriConverter` already performs when an operation is supplied. This forces a `400 Bad Request` response for cross-type IRIs instead of a silent assignment. ## Workarounds Declare a PHP type on every writable relation property (e.g. `public ?Foo $relation = null;` instead of `@var Foo $relation`). Symfony's `PropertyAccessor` will then reject a mismatched object with `InvalidTypeException`. This does not cover collections of mixed-type interfaces; upgrading to a patched version is the only complete fix. ## Proof of concept A functional test posts a `Bar` IRI to a `Foo`-declared relation on an untyped property. Without the fix the server responds with `HTTP 201` and the Bar IRI appears in the response payload. With the fix the server responds with `HTTP 400` (`Invalid IRI "/bars/1"`). Full PoC: `tests/Functional/Security/TypeConfusionRelationIriTest.php` in the patched branches. ## References - `src/Serializer/AbstractItemNormalizer.php` — vulnerable relation IRI load - `src/Symfony/Routing/IriConverter.php` — conditional `is_a` guard (operation-aware path) ## Credit Reported by @alexandre-daubois.

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. #[ApiProperty(security: ...)] is evaluated per request to decide whether a property is exposed. The componentsCache arrays in ApiPlatform\JsonApi\Serializer\ItemNormalizer and ApiPlatform\Hal\Serializer\ItemNormalizer are keyed on $context['cache_key'], which is set unconditionally before delegating to the parent normalizer. The component structure (attributes, relationships, links) computed for one request can therefore be reused for a subsequent request whose user has a different set of accessible properties. A user with lower privileges may end up seeing the structure of properties that the security predicate would otherwise have hidden for them. This issue has been fixed in versions 4.1.29, 4.2.26, and 4.3.12.