API Platform Core: Missing IRI type check enables resource type confusion

Summary

API Platform Core is a system to create hypermedia-driven REST and GraphQL APIs. In versions prior to 4.1.30, 4.2.26 and 4.3.12, the 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. 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. This issue has been fixed in versions 4.1.30, 4.2.26 and 4.3.12.

Timeline

1. Jul 1, 2026, 7:14 PM UTCCVE published
2. Jul 2, 2026, 3:50 PM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: partial

3. Jul 2, 2026, 3:50 PM UTCRecord last updated

Affected versions

• api-platform core

  fixed in 4.1.30; From 4.2.0 · fixed in 4.2.26; From 4.3.0 · fixed in 4.3.12

• api-platform/corePackagist

  fixed in 4.1.30

• api-platform/corePackagist

  From 4.2.0 · fixed in 4.2.26

• api-platform/corePackagist

  From 4.3.0 · fixed in 4.3.12

References 1