CVE-2026-62337
SNARK Verifier: Halo 2 aggregation mishandles point-at-infinity proof elements
SNARK Verifier is a generic (S)NARK verifier. Prior to 0.2.5, the Halo 2 aggregation circuit can mishandle proof points encoded as the point at infinity. EcPointLoader::multi_scalar_multiplication places a Value::Assigned(_) base paired with Value::Constant(ONE) into its unscaled variable-base list and passes it directly to sum_with_const. The default shim delegates to halo2-lib EccChip::sum, whose incomplete affine addition assumes nonidentity input points. A prover-controlled proof point encoded as (0, 0) can therefore enter the final aggregation sum through the scalar-one shortcut and affect the MSM or accumulator computation. Practical exploitability depends on the surrounding aggregation and final-decider checks; the advisory does not establish universal acceptance of invalid proofs. This issue is fixed in version 0.2.5.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
6.9
SNARK Verifier: Halo 2 aggregation mishandles point-at-infinity proof elements
SNARK Verifier is a generic (S)NARK verifier. Prior to 0.2.5, the Halo 2 aggregation circuit can mishandle proof points encoded as the point at infinity. EcPointLoader::multi_scalar_multiplication places a Value::Assigned(_) base paired with Value::Constant(ONE) into its unscaled variable-base list and passes it directly to sum_with_const. The default shim delegates to halo2-lib EccChip::sum, whose incomplete affine addition assumes nonidentity input points. A prover-controlled proof point encoded as (0, 0) can therefore enter the final aggregation sum through the scalar-one shortcut and affect the MSM or accumulator computation. Practical exploitability depends on the surrounding aggregation and final-decider checks; the advisory does not establish universal acceptance of invalid proofs. This issue is fixed in version 0.2.5.
- Record
CVE-2026-62337- CVSS 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 - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2026-114436
6.9
SNARK Verifier is a generic (S)NARK verifier. Prior to 0.2.5, the Halo 2 aggregation circuit can mishandle proof points encoded as the point at infinity. EcPointLoader::multi_scalar_multiplication places a Value::Assigned(_) base paired with Value::Constant(ONE) into its unscaled variable-base list and passes it directly to sum_with_const. The default shim delegates to halo2-lib EccChip::sum, whose incomplete affine addition assumes nonidentity input points. A prover-controlled proof point encoded as (0, 0) can therefore enter the final aggregation sum through the scalar-one shortcut and affect the MSM or accumulator computation. Practical exploitability depends on the surrounding aggregation and final-decider checks; the advisory does not establish universal acceptance of invalid proofs. This issue is fixed in version 0.2.5.
- Record
EUVD-2026-114436- CVSS 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 - Updated
- 2026-11-02
NVD
6.9
SNARK Verifier is a generic (S)NARK verifier. Prior to 0.2.5, the Halo 2 aggregation circuit can mishandle proof points encoded as the point at infinity. EcPointLoader::multi_scalar_multiplication places a Value::Assigned(_) base paired with Value::Constant(ONE) into its unscaled variable-base list and passes it directly to sum_with_const. The default shim delegates to halo2-lib EccChip::sum, whose incomplete affine addition assumes nonidentity input points. A prover-controlled proof point encoded as (0, 0) can therefore enter the final aggregation sum through the scalar-one shortcut and affect the MSM or accumulator computation. Practical exploitability depends on the surrounding aggregation and final-decider checks; the advisory does not establish universal acceptance of invalid proofs. This issue is fixed in version 0.2.5.
- Record
CVE-2026-62337- CVSS 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 - Weakness
- CWE-20
- Updated
- 2026-11-03
OSV
6.9
SNARK Verifier: Halo 2 aggregation mishandles point-at-infinity proof elements
SNARK Verifier is a generic (S)NARK verifier. Prior to 0.2.5, the Halo 2 aggregation circuit can mishandle proof points encoded as the point at infinity. EcPointLoader::multi_scalar_multiplication places a Value::Assigned(_) base paired with Value::Constant(ONE) into its unscaled variable-base list and passes it directly to sum_with_const. The default shim delegates to halo2-lib EccChip::sum, whose incomplete affine addition assumes nonidentity input points. A prover-controlled proof point encoded as (0, 0) can therefore enter the final aggregation sum through the scalar-one shortcut and affect the MSM or accumulator computation. Practical exploitability depends on the surrounding aggregation and final-decider checks; the advisory does not establish universal acceptance of invalid proofs. This issue is fixed in version 0.2.5.
- Record
CVE-2026-62337- CVSS 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 - Weakness
- CWE-20
- Updated
- 2026-11-04
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | NVD, OSV | |
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-62337 is a medium vulnerability (CVSS 6.9) in Axiom-crypto Snark-verifier, published October 30, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.30%, the 23rd percentile. No source names a fixed version.
References
github.com/axiom-crypto/snark-verifier/security/advisories/GHSA-x26x-7f4v-cqx7
github.com/axiom-crypto/halo2-lib/commit/f53be0939e2accf0dd7672b1a4abe80af73dadf3
github.com/axiom-crypto/snark-verifier/commit/bbfcc721d714bea0d44a27c8fc6c4736e73ca853
github.com/axiom-crypto/snark-verifier/releases/tag/v0.2.5
github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62337.json
nvd.nist.gov/vuln/detail/CVE-2026-62337