ParquetSharp: Possible Stack Overflow When Reading a ParquetFile with Large Decimal Type Width

Exploitation

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

CVSS

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

EPSS

• CVE-2026-42241: 0.27% estimated exploitation activity in the next 30 days; percentile 19.70 (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.

DecimalConverter.ReadDecimal makes a stackalloc using what might be an attacker-supplied value. If an attacker declares a decimal column with some unreasonable width, this could lead to a stack overflow. In a service environment, this would potentially take down a service. This affects applications using ParquetSharp to read untrusted Parquet files in a network service.

Published by the source

24 Apr 2026, 16:39 UTC

Last modified by the source

11 May 2026, 13:29 UTC

Source last checked

26 Oct 2026, 17:04 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-rrjr-v56m-ww88

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# Patch Next advisory brief: CVE-2026-42241

Advisory: ParquetSharp: Possible Stack Overflow When Reading a ParquetFile with Large Decimal Type Width
IDs: CVE-2026-42241, GHSA-rrjr-v56m-ww88
Record: https://patchnext.com/advisories/cve-2026-42241 (revision 1, source checked 26 Oct 2026, 17:04 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: parquetsharp 23.0.0.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- NuGet parquetsharp: affected >= 18.1.0, < 23.0.0.1; fixed in 23.0.0.1

## Suggested inspection (read-only)
- NuGet parquetsharp: 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 parquetsharp.
- 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-rrjr-v56m-ww88 (GitHub-reviewed advisory GHSA-rrjr-v56m-ww88 lists affected ranges: NuGet parquetsharp >=18.1.0 <23.0.0.1)

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