---
id: CVE-2026-62337
title: 'SNARK Verifier: Halo 2 aggregation mishandles point-at-infinity proof elements'
summary: >-
  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 pai…
severity: medium
cvss: 6.9
cvssVector: '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'
cvssSource: cna
cwe:
  - CWE-20
vendor: axiom-crypto
product: snark-verifier
affected:
  - snark-verifier < 0.2.5
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-11-02T14:58:24.604760Z'
published: '2026-10-30'
updated: '2026-11-02'
sourceUpdated: '2026-11-02T14:58:37.998Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-62337'
references:
  - url: >-
      https://github.com/axiom-crypto/snark-verifier/security/advisories/GHSA-x26x-7f4v-cqx7
    label: >-
      https://github.com/axiom-crypto/snark-verifier/security/advisories/GHSA-x26x-7f4v-cqx7
  - url: >-
      https://github.com/axiom-crypto/halo2-lib/commit/f53be0939e2accf0dd7672b1a4abe80af73dadf3
    label: >-
      https://github.com/axiom-crypto/halo2-lib/commit/f53be0939e2accf0dd7672b1a4abe80af73dadf3
  - url: >-
      https://github.com/axiom-crypto/snark-verifier/commit/bbfcc721d714bea0d44a27c8fc6c4736e73ca853
    label: >-
      https://github.com/axiom-crypto/snark-verifier/commit/bbfcc721d714bea0d44a27c8fc6c4736e73ca853
  - url: 'https://github.com/axiom-crypto/snark-verifier/releases/tag/v0.2.5'
    label: 'https://github.com/axiom-crypto/snark-verifier/releases/tag/v0.2.5'
tags:
  - cve.org
epss: 0.00301
epssPercentile: 0.2301
ingestedAt: '2026-11-05T19:30:42.675Z'
---

## Overview

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.

## Affected

- `snark-verifier < 0.2.5`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.