yt-dlp Project yt-dlp

A command inject vulnerability allows an attacker to perform command injection on Windows applications that indirectly depend on the CreateProcess function when the specific conditions are satisfied.

Published: 2024-04-10T15:22:56.099Z
Updated: 2025-11-18T17:35:41.547Z

`yt-dlp` and `youtube-dl` are command-line audio/video downloaders. Prior to the fixed versions, `yt-dlp` and `youtube-dl` do 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` and `youtube-dl` also read config from the working directory (and on Windows executables will be executed from the `yt-dlp` or `youtube-dl` directory), this could lead to arbitrary code being executed. `yt-dlp` version 2024.07.01 fixes this issue by whitelisting the allowed extensions. `youtube-dl` fixes this issue in commit `d42a222` on the `master` branch and in nightly builds tagged 2024-07-03 or later. This might mean some very uncommon extensions might not get downloaded, however it will also limit the possible exploitation surface. In addition to upgrading, have `.%(ext)s` at the end of the output template and make sure the user trusts the websites that they are downloading from. Also, make sure to never download to a directory within PATH or other sensitive locations like one's user directory, `system32`, or other binaries locations. For users who are not able to upgrade, keep the default output template (`-o "%(title)s [%(id)s].%(ext)s`); make sure the extension of the media to download is a common video/audio/sub/... one; try to avoid the generic extractor; and/or use `--ignore-config --config-location ...` to not load config from common locations.

Published: 2024-07-02T13:47:36.399Z
Updated: 2024-08-02T04:12:25.618Z

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.

Published: 2023-09-25T18:54:00.204Z
Updated: 2024-09-24T14:48:55.952Z