CVE-2026-90473 [MEDIUM] – msgpack-java through 0.9.12 contains an integer overflow vulnerability in MessageUnpacker.

msgpack-java through 0.9.12 contains an integer overflow vulnerability in MessageUnpacker.skipValue() when processing MAP32 containers with large element counts. Attackers can supply a MAP32 element count at or above 0x40000000 that wraps when doubled, causing the parser cursor to desynchronize and attacker-controlled data to be returned in place of later fields.