GHSA-79w7-vh3h-8g4j
HIGHyt-dlp File system modification and RCE through improper file-extension sanitization
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
yt-dlpReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
yt-dlp does not limit the extensions of downloaded files, which could lead to arbitrary filenames being created in the download folder (and path traversal on Windows). Since yt-dlp also reads config from the working directory (and on Windows executables will be executed from the yt-dlp directory) this could lead to arbitrary code being executed.
Patches
yt-dlp version 2024.07.01 fixes this issue by whitelisting the allowed extensions.
This means some very uncommon extensions might not get downloaded; however, it will also limit the possible exploitation surface.
Workarounds
It is recommended to upgrade yt-dlp to version 2024.07.01 as soon as possible, always have .%(ext)s at the end of the output template, and make sure you trust the websites that you are downloading from. Also, make sure to never download to a directory within PATH or other sensitive locations like your user directory, system32, or other binaries locations.
For users not able to upgrade:
- Make sure the extension of the media to download is a common video/audio/sub/... one
- Try to avoid the generic extractor (
--ies default,-generic) - Keep the default output template (
-o "%(title)s [%(id)s].%(ext)s) - Omit any of the subtitle options (
--write-subs,--write-auto-subs,--all-subs,--write-srt) - Use
--ignore-config --config-location ...to not load config from common locations
Details
One potential exploitation might look like this:
From a mimetype we do not know, we default to trimming the leading bit and using the remainder. Given a webpage that contains
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "VideoObject",
"name": "ffmpeg",
"encodingFormat": "video/exe",
"contentUrl": "https://example.com/video.mp4"
}
</script>
this will try and download a file called ffmpeg.exe (-o "%(title)s.%(ext)s).
ffmpeg.exe will be searched for in the current directory, and so upon the next run arbitrary code can be executed.
Alternatively, when engineering a file called yt-dlp.conf to be created, the config file could contain --exec ... and so would also execute arbitrary code.
Acknowledgement
A big thanks to @JarLob for independently finding a new application of the same underlying issue. More can be read about on the dedicated GitHub Security Lab disclosure here: Path traversal saving subtitles (GHSL-2024-090)
References
- https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-79w7-vh3h-8g4j
- https://nvd.nist.gov/vuln/detail/CVE-2024-38519
- https://github.com/yt-dlp/yt-dlp/releases/tag/2024.07.01
- https://github.com/yt-dlp/yt-dlp/commit/5ce582448ececb8d9c30c8c31f58330090ced03a
- https://securitylab.github.com/advisories/GHSL-2024-090_yt-dlp
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | yt-dlp | all versions | 2024.07.01 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for yt-dlp. 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 yt-dlp to 2024.07.01 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-79w7-vh3h-8g4j 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 GHSA-79w7-vh3h-8g4j 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 GHSA-79w7-vh3h-8g4j. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-79w7-vh3h-8g4j in your dependencies?
O3 detects GHSA-79w7-vh3h-8g4j across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.