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🐍 PyPI

CVE-2023-40581

HIGH

yt-dlp command injection when using `%q` in `--exec` on Windows

Also known asGHSA-42h4-v29r-42qg
Published
Sep 25, 2023
Updated
Apr 10, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
1 known

EPSS Exploitation Probability

via FIRST.org ↗
1.3%probability of exploitation in next 30 days
Lower Risk67th percentile-11.69%
0.00%5.63%11.3%16.9%4.8%1.3%Dec 25Apr 26Jun 26

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

1 pkg affected
🐍yt-dlp

Real-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

yt-dlp is a youtube-dl fork with additional features and fixes. yt-dlp allows the user to provide shell command lines to be executed at various stages in its download steps through the --exec flag. This flag allows output template expansion in its argument, so that metadata values may be used in the shell commands. The metadata fields can be combined with the %q conversion, which is intended to quote/escape these values so they can be safely passed to the shell. However, the escaping used for cmd (the shell used by Python's subprocess on Windows) does not properly escape special characters, which can allow for remote code execution if --exec is used directly with maliciously crafted remote data. This vulnerability only impacts yt-dlp on Windows, and the vulnerability is present regardless of whether yt-dlp is run from cmd or from PowerShell. Support for output template expansion in --exec, along with this vulnerable behavior, was added to yt-dlp in version 2021.04.11. yt-dlp version 2023.09.24 fixes this issue by properly escaping each special character. \n will be replaced by \r as no way of escaping it has been found. It is recommended to upgrade yt-dlp to version 2023.09.24 as soon as possible. Also, always be careful when using --exec, because while this specific vulnerability has been patched, using unvalidated input in shell commands is inherently dangerous. For Windows users who are not able to upgrade: 1. Avoid using any output template expansion in --exec other than {} (filepath). 2. If expansion in --exec is needed, verify the fields you are using do not contain ", | or &. 3. Instead of using --exec, write the info json and load the fields from it instead.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIyt-dlp2021.04.11&&< 2023.09.242023.09.24
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Detection & mitigation playbook

Open-source dependency
  1. Detect

    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.

  2. Fix

    Update yt-dlp to 2023.09.24 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-40581 is resolved across your whole dependency graph.

  3. 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.

  4. How O3 protects you

    O3 pinpoints whether CVE-2023-40581 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-2023-40581. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

yt-dlp is a youtube-dl fork with additional features and fixes. yt-dlp allows the user to provide shell command lines to be executed at various stages in its download steps through the `--exec` flag. This flag allows output template expansion in its argument, so that metadata values may be used in the shell commands. The metadata fields can be combined with the `%q` conversion, which is intended to quote/escape these values so they can be safely passed to the shell. However, the escaping used for `cmd` (the shell used by Python's `subprocess` on Windows) does not properly escape special charac
O3 Security · Impact-Aware SCA

Is CVE-2023-40581 in your dependencies?

O3 detects CVE-2023-40581 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.