CVE-2026-42241 ParquetSharp: Possible Stack Overflow When Reading a ParquetFile with Large Decimal Type Width
Attackers can cause a stack overflow and service crash by providing a Parquet file with an excessively large decimal column width.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-42241?
CVE-2026-42241 is a medium-severity denial of service vulnerability in G-Research ParquetSharp, published on 7 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
ParquetSharp is a .NET library for reading and writing Apache Parquet files. From version 18.1.0 to before version 23.0.0.1, 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. This issue has been patched in version 23.0.0.1.
Weakness: CWE-789
Which versions are affected by CVE-2026-42241?
2 open source packages ship an affected version, including ParquetSharp.
| Package | Affected | Fixed in |
|---|---|---|
ParquetSharp NuGet | From 18.1.0 | 23.0.0.1 |
ParquetSharp NuGet | From 18.1.0 | 23.0.0.1 |
How do I fix CVE-2026-42241?
Upgrade ParquetSharp to 23.0.0.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-42241 being exploited?
There is no known exploitation of CVE-2026-42241 in the wild and no public exploit code.
Sources
Also known as GHSA-rrjr-v56m-ww88.