{"id":"CVE-2026-32129","summary":"Poseidon V1 variable-length input collision via implicit zero-padding","details":"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() \u003c T - 1), unused rate positions are implicitly zero-filled. This allows trivial hash collisions: for any input vector [m1, ..., mk] hashed with a sponge of rate \u003e k, hash([m1, ..., mk]) equals hash([m1, ..., mk, 0]) because both produce identical pre-permutation states. This affects any use of PoseidonSponge or poseidon_hash where the number of inputs is less than T - 1 (e.g., hashing 1 input with T=3). Poseidon2 (Poseidon2Sponge) is not affected.","aliases":["GHSA-g2p6-hh5v-7hfm"],"modified":"2026-04-02T13:25:07.757241Z","published":"2026-03-12T17:47:10.717Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32129.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-328"]},"references":[{"type":"WEB","url":"https://github.com/stellar/rs-soroban-poseidon/releases/tag/v25.0.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32129.json"},{"type":"ADVISORY","url":"https://github.com/stellar/rs-soroban-poseidon/security/advisories/GHSA-g2p6-hh5v-7hfm"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-32129"},{"type":"FIX","url":"https://github.com/stellar/rs-soroban-poseidon/pull/10"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/stellar/rs-soroban-poseidon","events":[{"introduced":"0"},{"fixed":"024fc7a7a4fbad6f09102879fe15b3daf87a016c"}]}],"versions":["v25.0.0","v25.0.0-rc.1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-32129.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"}]}