GHSA-W567-GJR2-HM5J MessagePack-CSharp: Unity unsafe blit formatter allocates from unbounded byte length

Summary UnsafeBlitFormatterBase.Deserialize reads an attacker-controlled byteLength from an extension payload and allocates an array based on that value before validating it against the extension header length or remaining payload bytes. The outer extension header is bounded by available input, b...