GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

GHSA-79W7-VH3H-8G4J

Vulnerability from github – Published: 2024-07-02 15:58 – Updated: 2024-07-05 17:54
VLAI
Summary
yt-dlp File system modification and RCE through improper file-extension sanitization
Details

Summary

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.

Patches

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.

Workarounds

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: - Make sure the extension of the media to download is a common video/audio/sub/... one - Try to avoid the generic extractor (--ies default,-generic) - Keep the default output template (-o "%(title)s [%(id)s].%(ext)s) - Omit any of the subtitle options (--write-subs, --write-auto-subs, --all-subs, --write-srt) - Use --ignore-config --config-location ... to not load config from common locations

Details

One 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.

Acknowledgement

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)

References

  • https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-79w7-vh3h-8g4j
  • https://nvd.nist.gov/vuln/detail/CVE-2024-38519
  • https://github.com/yt-dlp/yt-dlp/releases/tag/2024.07.01
  • https://github.com/yt-dlp/yt-dlp/commit/5ce582448ececb8d9c30c8c31f58330090ced03a
  • https://securitylab.github.com/advisories/GHSL-2024-090_yt-dlp
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "yt-dlp"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2024.07.01"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2024-38519"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-434",
      "CWE-669"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2024-07-02T15:58:35Z",
    "nvd_published_at": "2024-07-02T14:15:13Z",
    "severity": "HIGH"
  },
  "details": "### Summary\n`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.\n\n### Patches\n`yt-dlp` version 2024.07.01 fixes this issue by whitelisting the allowed extensions.\nThis means some very uncommon extensions might not get downloaded; however, it will also limit the possible exploitation surface.\n\n### Workarounds\nIt 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.\n\nFor users not able to upgrade:\n- Make sure the extension of the media to download is a common video/audio/sub/... one\n- Try to avoid the generic extractor (`--ies default,-generic`)\n- Keep the default output template (`-o \"%(title)s [%(id)s].%(ext)s`)\n- Omit any of the subtitle options (`--write-subs`, `--write-auto-subs`, `--all-subs`, `--write-srt`)\n- Use `--ignore-config --config-location ...` to not load config from common locations\n\n### Details\nOne potential exploitation might look like this:\n\nFrom a mimetype we do not know, we default to trimming the leading bit and using the remainder. Given a webpage that contains\n```html\n\u003cscript type=\"application/ld+json\"\u003e\n{\n    \"@context\": \"https://schema.org\",\n    \"@type\": \"VideoObject\",\n    \"name\": \"ffmpeg\",\n    \"encodingFormat\": \"video/exe\",\n    \"contentUrl\": \"https://example.com/video.mp4\"\n}\n\u003c/script\u003e\n```\nthis will try and download a file called `ffmpeg.exe` (`-o \"%(title)s.%(ext)s`).\n`ffmpeg.exe` will be searched for in the current directory, and so upon the next run arbitrary code can be executed.\n\nAlternatively, when engineering a file called `yt-dlp.conf` to be created, the config file could contain `--exec ...` and so would also execute arbitrary code.\n\n### Acknowledgement\nA big thanks to @JarLob for independently finding a new application of the same underlying issue.\nMore can be read about on the dedicated GitHub Security Lab disclosure here: [Path traversal saving subtitles (GHSL-2024-090)](\u003chttps://securitylab.github.com/advisories/GHSL-2024-090_yt-dlp\u003e)\n\n### References\n- https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-79w7-vh3h-8g4j\n- https://nvd.nist.gov/vuln/detail/CVE-2024-38519\n- https://github.com/yt-dlp/yt-dlp/releases/tag/2024.07.01\n- https://github.com/yt-dlp/yt-dlp/commit/5ce582448ececb8d9c30c8c31f58330090ced03a\n- https://securitylab.github.com/advisories/GHSL-2024-090_yt-dlp\n",
  "id": "GHSA-79w7-vh3h-8g4j",
  "modified": "2024-07-05T17:54:51Z",
  "published": "2024-07-02T15:58:35Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/dirkf/youtube-dl/security/advisories/GHSA-22fp-mf44-f2mq"
    },
    {
      "type": "WEB",
      "url": "https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-79w7-vh3h-8g4j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-38519"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ytdl-org/youtube-dl/pull/32830"
    },
    {
      "type": "WEB",
      "url": "https://github.com/yt-dlp/yt-dlp/commit/5ce582448ececb8d9c30c8c31f58330090ced03a"
    },
    {
      "type": "WEB",
      "url": "https://github.com/ytdl-org/youtube-dl/commit/d42a222ed541b96649396ef00e19552aef0f09ec"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/yt-dlp/yt-dlp"
    },
    {
      "type": "WEB",
      "url": "https://github.com/yt-dlp/yt-dlp/releases/tag/2024.07.01"
    },
    {
      "type": "ADVISORY",
      "url": "https://securitylab.github.com/advisories/GHSL-2024-089_youtube-dl"
    },
    {
      "type": "ADVISORY",
      "url": "https://securitylab.github.com/advisories/GHSL-2024-090_yt-dlp"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "yt-dlp File system modification and RCE through improper file-extension sanitization"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.