gnark unsoundness in variable comparison / non-unique binary decomposition

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.5 · CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

EPSS

• CVE-2023-44378: 0.23% estimated exploitation activity in the next 30 days; percentile 14.39 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact For some in-circuit values, it is possible to construct two valid decomposition to bits. In addition to the canonical decomposition of a, for small values there exists a second decomposition for a+r (where r is the modulus the values are being reduced by). The second decomposition was possible due to overflowing the field where the values are defined. Internally, the comparison methods frontend.API.Cmp and frontend.API.IsLess used binary decomposition and checked the bitwise differences. This allows a malicious prover to construct a valid proof for a statement a < b even if a b. The issue impacts all users using API.Cmp or API.IsLess methods. Additionally, it impacts the users using bits.ToBinary or API.ToBinary methods if full-width decomposition is requested (the default behaviour if no options are given). The issues does not impact comparison methods in field emulation (package std/math/emulated) and dedicated comparison package (std/math/cmp). Patches Fix has been…

Published by the source

4 Oct 2023, 14:44 UTC

Last modified by the source

11 Nov 2023, 05:01 UTC

Source last checked

26 Oct 2026, 15:00 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-498w-5j49-vqjg

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# Patch Next advisory brief: CVE-2023-44378

Advisory: gnark unsoundness in variable comparison / non-unique binary decomposition
IDs: CVE-2023-44378, GHSA-498w-5j49-vqjg
Record: https://patchnext.com/advisories/cve-2023-44378 (revision 1, source checked 26 Oct 2026, 15:00 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/consensys/gnark 0.9.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/consensys/gnark: affected < 0.9.0; fixed in 0.9.0

## Suggested inspection (read-only)
- Go github.com/consensys/gnark: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/consensys/gnark.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-498w-5j49-vqjg (GitHub-reviewed advisory GHSA-498w-5j49-vqjg lists affected ranges: Go github.com/consensys/gnark >=0 <0.9.0)

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