CVE-2026-44288: protobufjs has overlong UTF-8 decoding

protobufjs includes a minimal UTF-8 decoder used in non-Node and fallback decoding paths. The affected decoder accepted overlong UTF-8 byte sequences and decoded them to their canonical characters instead of replacing them.

The issue concerns overlong encodings and code points outside the Unicode range. protobufjs may still accept some non-strict UTF-8 input for compatibility, so applications should not rely on protobufjs as a general-purpose strict UTF-8 validator.