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Bugzilla – Full Text Bug Listing |
| Summary: | VUL-0: CVE-2023-40581: yt-dlp: template expansion in `--exec` flag | ||
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| Product: | [openSUSE] openSUSE Distribution | Reporter: | SMASH SMASH <smash_bz> |
| Component: | Security | Assignee: | Jan Engelhardt <jengelh> |
| Status: | RESOLVED INVALID | QA Contact: | Security Team bot <security-team> |
| Severity: | Major | ||
| Priority: | P3 - Medium | CC: | camila.matos, rfrohl |
| Version: | Leap 15.6 | ||
| Target Milestone: | --- | ||
| Hardware: | Other | ||
| OS: | Other | ||
| URL: | https://smash.suse.de/issue/379815/ | ||
| Whiteboard: | |||
| Found By: | Security Response Team | Services Priority: | |
| Business Priority: | Blocker: | --- | |
| Marketing QA Status: | --- | IT Deployment: | --- |
Already fixed in Factory, still pending for openSUSE:Backports:SLE-15-SP* new bot eating references: https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-42h4-v29r-42qg https://github.com/yt-dlp/yt-dlp/releases/tag/2023.09.24 https://github.com/yt-dlp/yt-dlp/commit/de015e930747165dbb8fcd360f8775fd973b7d6e The bug was closed as this looks to be an issue that only affects Windows systems. |
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. References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2023-40581