---
id: "CVE-2026-62337"
kind: "vulnerability"
aliases: ["CVE-2026-62337"]
title: "SNARK Verifier: point-at-infinity input can corrupt final proof aggregation sum"
severity: "medium"
cvss: 6.9
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["halo2", "package", "rust", "snark-verifier", "zk-proofs"]
not_affected_if: ["no-halo2-aggregation", "trusted-prover-only"]
published_at: "2026-10-30T20:17:12+00:00"
first_seen_at: "2026-10-30T20:25:39+00:00"
updated_at: "2026-10-30T20:26:43+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-62337", "first_seen_at": "2026-10-30T20:25:39+00:00"}]
---

# SNARK Verifier: point-at-infinity input can corrupt final proof aggregation sum

SNARK Verifier is a generic (S)NARK verifier library; before 0.2.5 a prover-supplied proof point encoded as (0, 0) can enter the Halo 2 aggregation sum through a scalar-one shortcut. An attacker who controls a proof may influence the multi-scalar multiplication or accumulator result, though the advisory does not establish that invalid proofs are universally accepted.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed `snark-verifier` crate version in `Cargo.lock` and confirm whether it is below `0.2.5`.
- Look for uses of the Halo 2 aggregation circuit or `EcPointLoader::multi_scalar_multiplication` in your verifier code.

## Fix

- `snark-verifier` `0.2.5`

## Timeline

- 2026-10-30T20:25:39+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-62337

## From the sources

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.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_