| Full Fuzzer Name | OneOfMultipleBranchesMergedFieldsFuzzer |
| Log Key | OOMBMFF |
| Description | Merges properties from two distinct OpenAPI oneOf branches into a single JSON object to verify that the API enforces exclusive oneOf semantics (expecting 4XX) rather than anyOf. |
| Enabled by default? | Yes (included in ci, crash, and full profiles) |
| Target field types | Request body objects (root or nested) composed with oneOf (>= 2 branches) |
| Expected result when fuzzed field is required | 4XX |
| Expected result when fuzzed field is optional | 4XX |
| Expected result when fuzzed value is not matching field pattern | 4XX |
| Fuzzing logic | Takes a valid payload matching one oneOf branch and injects non-discriminator properties from a second oneOf branch into the same JSON object. |
| Conditions when this fuzzer will be skipped | When the payload is not a JSON object or contains no oneOf schema with distinct branch properties. |
| HTTP methods that will be skipped | GET, DELETE, HEAD, TRACE |
| Reporting | Reports error if the server accepts the merged multi-branch payload with 2XX or fails with 5XX; reports success when rejected with 4XX. |