A vulnerability in the async JSON parser of jackson-core allows bypassing the maxNumberLength constraint, enabling parsing of arbitrarily long numbers. This leads to excessive memory allocation and potential CPU exhaustion, causing a Denial of Service (DoS). The synchronous parser enforces the limit correctly, but the async parser fails to validate number length due to skipped checks in its code path. This inconsistency creates a resource exhaustion risk when processing large numeric JSON values asynchronously.