Executive brief
Succinct Labs SP1 is a zero-knowledge virtual machine that allows developers to prove that a computer program was executed correctly without revealing the underlying data. A security flaw in the system's verification process could allow a malicious actor to submit a fraudulent proof that appears valid but actually represents incorrect or forged program execution. This undermines the core trust of the system, potentially allowing for data forgery or the misrepresentation of complex computations.
Technical details
A soundness vulnerability exists in the SP1 V6 recursive shard verifier due to a binding gap in the jagged Polynomial Commitment Scheme (PCS) verifier. The recursion circuit utilized separate witnesses for commitment binding (row counts) and polynomial evaluation (prefix sums) without enforcing a consistency check between them. A malicious prover can exploit this by supplying one trace shape for commitment binding and a different shape for evaluation, potentially misrepresenting circuit structure or data. While the native verifier is unaffected because it derives both parameters from a single object, the recursive circuit failed to constrain these witnesses. The issue is resolved in version 6.1.0 by adding a post-evaluation consistency constraint that reconstructs and asserts equality between the two witnesses.
Affected products
- Succinct Labs SP1 6.0.0 - 6.0.2
Timeline
- 2026-04-11: patched: Version 6.1.0 released
- 2026-04-11: advisory: GitHub Security Advisory GHSA-63x8-x938-vx33 published
- 2026-04-18: disclosed: CVE-2026-40323 published to NVD