gnark's range checker gadget allows wider inputs up to word alignment

Exploitation

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

CVSS

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

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Impact gnark provides a gadget in the standard library to allow optimized checking of the bitwidth of the inputs. The gadget works by constructing a fixed lookup table containing all valid entries, partitioning the input and checking that all parts are inside the lookup table. The range checker gadget did not take into account that the highest partition may be less than the width limit, allowing the inputs to be up to 16 bits wider than checked. Range checking gadget is extensively used in field emulation. Users using any dependant gadget (ECDSA verification, proof recursion etc.) is impacted. We consider the impact of the vulnerability being low as the number of attacker-modifiable bits is significantly smaller compared to the bit-width of scalar field modulus and it won't be possible to construct inputs which would allow to overflow the scalar field. Patches The issue has been patched in the stable branch of gnark. Due to low severity of the issue no emergency release will be…

Published by the source

12 Nov 2023, 15:56 UTC

Last modified by the source

12 Nov 2023, 15:56 UTC

Source last checked

26 Oct 2026, 15:00 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-rjjm-x32p-m3f7

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# Patch Next advisory brief: GHSA-rjjm-x32p-m3f7

Advisory: gnark's range checker gadget allows wider inputs up to word alignment
IDs: GHSA-rjjm-x32p-m3f7
Record: https://patchnext.com/advisories/ghsa-rjjm-x32p-m3f7 (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: Low (CVSS 3.2)
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 0.9.2. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/consensys/gnark: affected < 0.9.2; fixed in 0.9.2

## 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-rjjm-x32p-m3f7 (GitHub-reviewed advisory GHSA-rjjm-x32p-m3f7 lists affected ranges: Go github.com/consensys/gnark >=0 <0.9.2)

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