CVE-2026-55407 Buffa: Memory Exhaustion Denial of Service in decode_unknown_field via Unbounded Allocation

Buffa is a pure-Rust Protocol Buffers implementation with first-class protobuf editions support. Prior to 0.8.0, the decodeunknownfield function in buffa's protobuf decoder allocated heap memory in proportion to untrusted input unknown fields in the serialized protobuf without enforcing an...