Description
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.
Published: 2026-10-30
Score: 6.9 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

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Advisories

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History

Fri, 30 Oct 2026 20:15:00 +0000

Type Values Removed Values Added
Description 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.
Title SNARK Verifier: Halo 2 aggregation mishandles point-at-infinity proof elements
Weaknesses CWE-20
References
Metrics cvssV4_0

{'score': 6.9, 'vector': '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'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-30T20:00:55.328Z

Reserved: 2026-07-13T21:42:50.094Z

Link: CVE-2026-62337

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-30T20:17:12.780

Modified: 2026-10-30T20:17:12.780

Link: CVE-2026-62337

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

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Weaknesses