{"id":"CVE-2026-50019","aliases":["GHSA-f7j3-774f-rfhj","PYSEC-2026-3431"],"url":"https://o3.security/vulnerability/CVE-2026-50019","summary":"yt-dlp: File Downloader cookie leak with curl","details":"### Summary\nIf curl is used an external downloader for yt-dlp, cookies may be leaked to an unintended host upon HTTP redirect or when the host for download fragments differs from their parent manifest's.\n\nThis is the equivalent to [GHSA-v8mc-9377-rwjj](<https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-v8mc-9377-rwjj>) for the `curl` downloader. The vulnerable behavior is present in [yt-dlp](https://github.com/yt-dlp/yt-dlp) released since 2023.09.24.\n\n### Details\nAt the file download stage, the cookies are passed by yt-dlp to the file downloader via `--cookie`. However, unless these are loaded from a file, this operation does not activate the cookie engine. As a result, `curl` will send cookies with requests to domains or paths for which the cookies are not scoped.\n\nAn example of a potential attack scenario exploiting this vulnerability:\n1. an attacker has crafted a malicious website with an embedded URL designed to be detected by yt-dlp as a video download. This embedded URL has the domain of a trusted site that the user has loaded cookies for, and conducts an [unvalidated redirect](https://cheatsheetseries.owasp.org/cheatsheets/Unvalidated_Redirects_and_Forwards_Cheat_Sheet.html) to a target URL.\n2. yt-dlp extracts this URL and calculates the cookies which are then passed to `curl`.\n3. the download URL redirects to a server controlled by the attacker, to which `curl` forwards the user's sensitive cookie information.\n\n### Patches\nyt-dlp version 2026.06.09 fixes this issue by doing the following:\n\n- Pass the cookies through stdin via `--cookie -` if `curl` is version 7.59 or higher.\n- Pass the cookies via `--cookie /dev/fd/0` if the system supports this device file.\n- In all other cases create a temporary file, save the cookies and then pass via `--cookie <file>`.\n\n### Workarounds\nIt is recommended to upgrade yt-dlp to version 2026.06.09 as soon as possible.\n\nFor users who are not able to upgrade:\n\n- Do not use `--downloader curl`.","published":"2026-06-23T16:13:26.676Z","modified":"2026-08-12T03:51:09.072132284Z","cvss":{"score":6.1,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:N/A:N"},"epss":{"score":0.00319,"percentile":0.2436,"asOf":"2026-09-01"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"yt-dlp","fixedVersion":"2026.6.9"}],"fix":{"url":"https://github.com/yt-dlp/yt-dlp/commit/2726572520238356bcf64aba2040228648b44c82","label":"yt-dlp/yt-dlp@2726572"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/50xxx/CVE-2026-50019.json"},{"type":"ADVISORY","url":"https://github.com/yt-dlp/yt-dlp/security/advisories/GHSA-f7j3-774f-rfhj"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50019"},{"type":"WEB","url":"https://github.com/yt-dlp/yt-dlp/commit/2726572520238356bcf64aba2040228648b44c82"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-f7j3-774f-rfhj"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/yt-dlp/PYSEC-2026-3431.yaml"},{"type":"PACKAGE","url":"https://github.com/yt-dlp/yt-dlp"},{"type":"WEB","url":"https://github.com/yt-dlp/yt-dlp-nightly-builds/releases/tag/2026.06.09.230517"},{"type":"WEB","url":"https://github.com/yt-dlp/yt-dlp/releases/tag/2026.06.09"},{"type":"WEB","url":"https://pypi.org/project/yt-dlp"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:09.072132284Z"}}