CVE-2023-40581 is a high-severity (CVSS 8.3) OS Command Injection vulnerability in yt-dlp. 1 public exploit reference exists, so weaponization risk is real. A fix is available for yt-dlp — see the affected versions and patch details below.
yt-dlp command injection when using `%q` in `--exec` on Windows
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.
How urgent is this, really
CVE-2023-40581 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
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
Impact
yt-dlp allows the user to provide shell commands to be executed at various stages in its download process through the --exec flag. This flag allows output template expansion in its argument, so that video 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) did 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 https://youtu.be/Jo66yyCpHcQ --exec "echo %(title)q"
[youtube] Extracting URL: https://youtu.be/Jo66yyCpHcQ
[youtube] Jo66yyCpHcQ: Downloading webpage
[youtube] Jo66yyCpHcQ: Downloading ios player API JSON
[youtube] Jo66yyCpHcQ: Downloading android player API JSON
[youtube] Jo66yyCpHcQ: Downloading m3u8 information
[info] Jo66yyCpHcQ: Downloading 1 format(s): 135+251
[download] Destination: ＂&echo(&echo(pwned&rem( [Jo66yyCpHcQ].f135.mp4
[download] 100% of 4.85KiB in 00:00:00 at 60.20KiB/s
[download] Destination: ＂&echo(&echo(pwned&rem( [Jo66yyCpHcQ].f251.webm
[download] 100% of 4.80KiB in 00:00:00 at 31.58KiB/s
[Merger] Merging formats into "＂&echo(&echo(pwned&rem( [Jo66yyCpHcQ].mkv"
Deleting original file ＂&echo(&echo(pwned&rem( [Jo66yyCpHcQ].f135.mp4 (pass -k to keep)
Deleting original file ＂&echo(&echo(pwned&rem( [Jo66yyCpHcQ].f251.webm (pass -k to keep)
[Exec] Executing command: echo "\"&echo(&echo(pwned&rem("
"\"
pwned
Patches
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.
Workarounds
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:
- Avoid using any output template expansion in
--execother than{}(filepath). - If expansion in
--execis needed, verify the fields you are using do not contain",|or&. - Instead of using
--exec, write the info json and load the fields from it instead.
References
- https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-42h4-v29r-42qg
- https://nvd.nist.gov/vuln/detail/CVE-2023-40581
- https://github.com/yt-dlp/yt-dlp/releases/tag/2023.09.24
- https://github.com/yt-dlp/yt-dlp-nightly-builds/releases/tag/2023.09.24.003044
- https://github.com/yt-dlp/yt-dlp/commit/de015e930747165dbb8fcd360f8775fd973b7d6e
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | yt-dlp | ≥ 2021.04.11&&< 2023.09.24 | 2023.09.24pip install --upgrade 'yt-dlp==2023.09.24' |
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 dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for yt-dlp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2023-40581 can be triaged on real exposure rather than presence alone.
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
Is CVE-2023-40581 in your dependencies?
O3 Security finds CVE-2023-40581 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.