CVE-2024-22423

The patch that addressed CVE-2023-40581 attempted to prevent RCE when using --exec with %q by replacing double quotes with two double quotes.
However, this escaping is not sufficient, and still allows expansion of environment variables.

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/42xO6rVqf2E" --ignore-config -f 18 --exec "echo %(title)q"
[youtube] Extracting URL: https://youtu.be/42xO6rVqf2E
[youtube] 42xO6rVqf2E: Downloading webpage
[youtube] 42xO6rVqf2E: Downloading ios player API JSON
[youtube] 42xO6rVqf2E: Downloading android player API JSON
[youtube] 42xO6rVqf2E: Downloading m3u8 information
[info] 42xO6rVqf2E: Downloading 1 format(s): 18
[download] Destination: %CMDCMDLINE：~-1%&echo pwned&calc.exe [42xO6rVqf2E].mp4
[download] 100% of  126.16KiB in 00:00:00 at 2.46MiB/s
[Exec] Executing command: echo "%CMDCMDLINE:~-1%&echo pwned&calc.exe"
""
pwned

Workarounds

It is recommended to upgrade yt-dlp to version 2024.04.09 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 --exec other than {} (filepath).
• If expansion in --exec is 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.

Details

When escaping variables, the following code is used for Windows.
yt_dlp/compat/__init__.py line 31-33

    def compat_shlex_quote(s):
        import re
        return s if re.match(r'^[-_\w./]+$', s) else s.replace('"', '""').join('""')

It replaces " with "" to balance out the quotes and keep quoting intact if non-allowed characters are included. However, the %CMDCMDLINE% variable can be used to generate a quote using %CMDCMDLINE:~-1%; since the value of %CMDCMDLINE% is the commandline with which cmd.exe was called, and it is always called with the command surrounded by quotes, %CMDCMDLINE:~-1% expands to ". After the quotes have been unbalanced, special characters are no longer quoted and commands can be executed:

%CMDCMDLINE:~-1%&calc.exe

References

• https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-hjq6-52gw-2g7p
• https://nvd.nist.gov/vuln/detail/CVE-2024-22423
• https://github.com/yt-dlp/yt-dlp/releases/tag/2024.04.09
• https://github.com/yt-dlp/yt-dlp/commit/ff07792676f404ffff6ee61b5638c9dc1a33a37a

Untrusted input reaches a shell command, allowing arbitrary commands to run on the host. Typical impact: code execution in the application's environment.

CVE-2024-22423 has a CVSS score of 8.3 (High). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2024.04.09); upgrading removes the vulnerable code path.

Kodem intelligence

yt-dlp version 2024.04.09 fixes this issue by properly escaping %. It replaces them with %%cd:~,%, a variable that expands to nothing, leaving only the leading percent.

1. What is CVE-2024-22423? CVE-2024-22423 is a high-severity OS command injection vulnerability in yt-dlp (pip), affecting versions >= 2021.04.11, < 2024.04.09. It is fixed in 2024.04.09. Untrusted input reaches a shell command, allowing arbitrary commands to run on the host.
2. How severe is CVE-2024-22423? CVE-2024-22423 has a CVSS score of 8.3 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of yt-dlp are affected by CVE-2024-22423? yt-dlp (pip) versions >= 2021.04.11, < 2024.04.09 is affected.
4. Is there a fix for CVE-2024-22423? Yes. CVE-2024-22423 is fixed in 2024.04.09. Upgrade to this version or later.
5. Is CVE-2024-22423 exploitable, and should I be worried? Whether CVE-2024-22423 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2024-22423 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2024-22423? Upgrade yt-dlp to 2024.04.09 or later.