Vulnerability · Published Sep 25, 2023 · Assigned by GitHub_M
CVE-2023-40581yt-dlp command injection when using `%q` in `--exec` on Windows
High 8.4
In plain English
A high-severity OS command injection in yt-dlp from yt-dlp. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.3% (higher than 71% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | yt-dlp | 0-r0 | ALPINE-CVE-2023-40581 |
| Alpine:v3.21 | yt-dlp | 0-r0 | ALPINE-CVE-2023-40581 |
| Alpine:v3.22 | yt-dlp | 0-r0 | ALPINE-CVE-2023-40581 |
| Alpine:v3.23 | yt-dlp | 0-r0 | ALPINE-CVE-2023-40581 |
| Alpine:v3.24 | yt-dlp | 0-r0 | ALPINE-CVE-2023-40581 |
| PyPI | yt-dlp | 2023.09.24 | GHSA-42h4-v29r-42qg |
| PyPI | yt-dlp | 2023.09.24 | PYSEC-2026-2064 |
Affected products (as reported)
Weakness: CWE-78 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
References
- https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-42h4-v29r-42qg x_refsource_CONFIRM
- https://github.com/yt-dlp/yt-dlp/commit/de015e930747165dbb8fcd360f8775fd973b7d6e x_refsource_MISC
- https://github.com/yt-dlp/yt-dlp-nightly-builds/releases/tag/2023.09.24.003044 x_refsource_MISC
- https://github.com/yt-dlp/yt-dlp/releases/tag/2021.04.11 x_refsource_MISC
- https://github.com/yt-dlp/yt-dlp/releases/tag/2023.09.24 x_refsource_MISC