CVE-2026-61618
SNARK Verifier: noncanonical accumulator limb decoding
SNARK Verifier is a generic (S)NARK verifier. Prior to 0.2.5, KZG accumulator public-instance limbs are decoded without consistently enforcing canonical limb bounds before elliptic-curve coordinate reconstruction. `PlonkProof::read` selects scalars using `accumulator_indices` and passes them to `AccumulatorEncoding::from_repr`. For the EVM loader, `LimbsEncoding::from_repr` forwards them to `EvmLoader::ec_point_from_limbs` in `snark-verifier/src/loader/evm/loader.rs`, where `shl` and `add` reconstruct coordinates before `validate_ec_point` checks the resulting affine point rather than the original limb bounds. The related native path in `snark-verifier/src/pcs/kzg/accumulator.rs` can reach assertion- or unwrap-based decoding and panic instead of returning a verification error. This allows noncanonical encodings at the verifier boundary and can crash the native verifier. Standard SDK aggregation circuits are expected to constrain accumulator limbs before this boundary, which limits practical exploitability. This issue is fixed in version 0.2.5.
Fixes and workarounds
No remediation reported in collected sources.
Missing remediation information is not evidence that no patch exists.
Affected products and versions
| Product | Versions | Authority |
|---|---|---|
| snark-verifier axiom-crypto |
< 0.2.5 (affected) | CNA: GitHub_M |
snark-verifiersnark-verifier
rust |
< 0.2.5 (affected, GitHub advisory range) | GitHub GHSA-265x-v3qf-ff6p |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 6.9 medium |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N | CNA: GitHub_M |
| 4.0 / 6.9 medium |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD: [email protected] |
Exploit evidence
No exploit evidence in collected sources. This is not proof of no exploitation.
References
- https://github.com/axiom-crypto/snark-verifier/security/advisories/GHSA-265x-v3qf-ff6pCNA: GitHub_M · x_refsource_CONFIRM
- https://github.com/axiom-crypto/snark-verifier/commit/d6aaf66d4706f5317cf61d5dbe00c14e7fbdbb70CNA: GitHub_M · x_refsource_MISC
- https://github.com/axiom-crypto/snark-verifier/releases/tag/v0.2.5CNA: GitHub_M · x_refsource_MISC
- https://github.com/axiom-crypto/snark-verifier/commit/d6aaf66d4706f5317cf61d5dbe00c14e7fbdbb70[email protected]
- https://github.com/axiom-crypto/snark-verifier/releases/tag/v0.2.5[email protected]
- https://github.com/axiom-crypto/snark-verifier/security/advisories/GHSA-265x-v3qf-ff6p[email protected]
- https://github.com/axiom-crypto/snark-verifier/security/advisories/GHSA-265x-v3qf-ff6pGitHub Security Advisories · advisory
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