CVE-2026-42241
MEDIUMCVE-2026-42241 is a medium-severity (CVSS 5.3) remote code execution vulnerability in ParquetSharp. O3 Security confirms whether CVE-2026-42241 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
ParquetSharp: Possible Stack Overflow When Reading a ParquetFile with Large Decimal Type Width
Real-World Exposure
ParquetSharpReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | ParquetSharp | ≥ 18.1.0&&< 23.0.0.1 | 23.0.0.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ParquetSharp. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update ParquetSharp to 23.0.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-42241 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-42241 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-42241. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-42241 in your dependencies?
O3 detects CVE-2026-42241 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.