The msgpack decoder fails to properly validate the input buffer length when processing truncated fixext data (format codes 0xd4-0xd8). This can lead to an out-of-bounds read and a runtime panic, allowing a denial of service attack.
https://securityinfinity.com/research/shamaton-msgpack-oob-panic-fixext-dos-2026
https://pkg.go.dev/vuln/GO-2026-4513