Hash collisions via implicit zero-filling
Published Mar 12, 2026 · Updated Mar 12, 2026
Weak hashing in soroban-poseidon before 25.0.1 allows remote attackers to create distinct Poseidon V1 inputs with identical hashes. The PoseidonSponge::compute_hash method accepts fewer inputs than its rate and leaves unused rate positions as zeros, so appending a zero produces the same pre-permutation state. Reachability requires a consuming Soroban contract to expose PoseidonSponge or poseidon_hash with fewer than T - 1 inputs; collisions can invalidate integrity assumptions in that contract.
Summary
What happened
Weak hashing in soroban-poseidon before 25.0.1 allows remote attackers to create distinct Poseidon V1 inputs with identical hashes. The PoseidonSponge::compute_hash method accepts fewer inputs than its rate and leaves unused rate positions as zeros, so appending a zero produces the same pre-permutation state. Reachability requires a consuming Soroban contract to expose PoseidonSponge or poseidon_hash with fewer than T - 1 inputs; collisions can invalidate integrity assumptions in that contract.
The record
- CVE
- CVE-2026-32129
- Published
- Mar 12, 2026
- Updated
- Mar 12, 2026
- Vendor
- Stellar Development Foundation
- Product
- soroban-poseidon
- Classifications
- CWE-328
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 12, 2026CVE publishedPublication date reported by the CVE source.
- Mar 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=< 25.0.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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