CVE-2026-32129 Poseidon V1 variable-length input collision via implicit zero-padding

soroban-poseidon provides Poseidon and Poseidon2 cryptographic hash functions for Soroban smart contracts. Poseidon V1 PoseidonSponge accepts variable-length inputs without injective padding. When a caller provides fewer inputs than the sponge rate inputs.len k, hashm1, ..., mk equals hashm1, ......