CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
13.2%
yt-dlp
does 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
also reads config from the working directory (and on Windows executables will be executed from the yt-dlp directory) this could lead to arbitrary code being executed.
yt-dlp
version 2024.07.01 fixes this issue by whitelisting the allowed extensions.
This means some very uncommon extensions might not get downloaded; however, it will also limit the possible exploitation surface.
It is recommended to upgrade yt-dlp to version 2024.07.01 as soon as possible, always have .%(ext)s
at the end of the output template, and make sure you trust the websites that you are downloading from. Also, make sure to never download to a directory within PATH or other sensitive locations like your user directory, system32
, or other binaries locations.
For users not able to upgrade:
--ies default,-generic
)-o "%(title)s [%(id)s].%(ext)s
)--write-subs
, --write-auto-subs
, --all-subs
, --write-srt
)--ignore-config --config-location ...
to not load config from common locationsOne potential exploitation might look like this:
From a mimetype we do not know, we default to trimming the leading bit and using the remainder. Given a webpage that contains
<script type="application/ld+json">
{
"@context": "https://schema.org",
"@type": "VideoObject",
"name": "ffmpeg",
"encodingFormat": "video/exe",
"contentUrl": "https://example.com/video.mp4"
}
</script>
this will try and download a file called ffmpeg.exe
(-o "%(title)s.%(ext)s
).
ffmpeg.exe
will be searched for in the current directory, and so upon the next run arbitrary code can be executed.
Alternatively, when engineering a file called yt-dlp.conf
to be created, the config file could contain --exec ...
and so would also execute arbitrary code.
A big thanks to @JarLob for independently finding a new application of the same underlying issue.
More can be read about on the dedicated GitHub Security Lab disclosure here: Path traversal saving subtitles (GHSL-2024-090)
github.com/dirkf/youtube-dl/security/advisories/GHSA-22fp-mf44-f2mq
github.com/yt-dlp/yt-dlp
github.com/yt-dlp/yt-dlp/commit/5ce582448ececb8d9c30c8c31f58330090ced03a
github.com/yt-dlp/yt-dlp/releases/tag/2024.07.01
github.com/yt-dlp/yt-dlp/security/advisories/GHSA-79w7-vh3h-8g4j
github.com/ytdl-org/youtube-dl/commit/d42a222ed541b96649396ef00e19552aef0f09ec
github.com/ytdl-org/youtube-dl/pull/32830
nvd.nist.gov/vuln/detail/CVE-2024-38519
securitylab.github.com/advisories/GHSL-2024-089_youtube-dl
securitylab.github.com/advisories/GHSL-2024-090_yt-dlp
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
AI Score
Confidence
High
EPSS
Percentile
13.2%