GHSA-P6PP-M3F8-5C89 jackson-core: ReDoS: quadratic backtracking in NumberInput.PATTERN_FLOAT via looksLikeValidNumber()

Status FULLY REPRODUCED with a clean, textbook empirical signature: measured runtime grew almost exactly 4x for every doubling of input size across five consecutive doublings 5,000 → 160,000 characters, confirming On² behavior. A single 160,000-character string smaller than a typical HTTP request...