CVE-2025-43858 is a critical-severity (CVSS 9.2) CWE-77 vulnerability in YoutubeDLSharp. O3 Security confirms whether CVE-2025-43858 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
YoutubeDLSharp allows command injection on windows system due to non sanitized arguments
Real-World Exposure
YoutubeDLSharpReal-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
YoutubeDLSharp is a wrapper for the command-line video downloaders youtube-dl and yt-dlp. In versions starting from 1.0.0-beta4 and prior to 1.1.2, an unsafe conversion of arguments allows the injection of a malicious commands when starting yt-dlp from a commands prompt running on Windows OS with the UseWindowsEncodingWorkaround value defined to true (default behavior). If a user is using built-in methods from the YoutubeDL.cs file, the value is true by default and a user cannot disable it from these methods. This issue has been patched in version 1.1.2.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| .NETNuGet | YoutubeDLSharp | ≥ 1.0.0-beta4&&< 1.1.2 | 1.1.2 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for YoutubeDLSharp. 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 YoutubeDLSharp to 1.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-43858 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-2025-43858 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-2025-43858. 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-2025-43858 in your dependencies?
O3 detects CVE-2025-43858 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.