How severe is GHSA-v8mc-9377-rwjj?

GHSA-v8mc-9377-rwjj has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-v8mc-9377-rwjj?

GHSA-v8mc-9377-rwjj affects the following packages: yt-dlp (PyPI). Ecosystems affected: PyPI.

How do I fix GHSA-v8mc-9377-rwjj?

Update yt-dlp to 2023.7.06 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v8mc-9377-rwjj is resolved across your whole dependency graph.

How do I detect GHSA-v8mc-9377-rwjj in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for yt-dlp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-v8mc-9377-rwjj if there is no patch (or I can't update yet)?

Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Is GHSA-v8mc-9377-rwjj actively exploited in the wild?

No public exploit code has been indexed for GHSA-v8mc-9377-rwjj yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-v8mc-9377-rwjj?

GHSA-v8mc-9377-rwjj has an EPSS (Exploit Prediction Scoring System) score of 1.0%, placing it in the 64th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-v8mc-9377-rwjj?

GHSA-v8mc-9377-rwjj is classified as Information Exposure (CWE-200), Open Redirect (CWE-601). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-v8mc-9377-rwjj published, and has it been updated?

GHSA-v8mc-9377-rwjj was published on July 6, 2023 and was last updated on September 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

MEDIUM severity

yt-dlp File Downloader cookie leakGHSA-v8mc-9377-rwjj

MEDIUMFix: yt-dlp/yt-dlp@1ceb657

GHSA-v8mc-9377-rwjj is a medium-severity (CVSS 6.1) Information Exposure vulnerability in yt-dlp. A fix is available for yt-dlp — see the affected versions and patch details below.

Also known asCVE-2023-35934PYSEC-2026-2067

Published

Jul 6, 2023

Updated

Sep 10, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-v8mc-9377-rwjj.

EPSS Exploitation Probability

via FIRST.org ↗

1.0%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs64th percentile — riskier than 64% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🐍yt-dlp

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Impact

During file downloads, yt-dlp or the external downloaders that yt-dlp employs may leak cookies on HTTP redirects to a different host, or leak them when the host for download fragments differs from their parent manifest's host.

This vulnerable behavior is present in all versions of youtube-dl, youtube-dlc and yt-dlp released since 2015.01.25. All native and external downloaders are affected, except for curl and httpie (httpie version 3.1.0 or later).

At the file download stage, all cookies are passed by yt-dlp to the file downloader as a Cookie header, thereby losing their scope. This also occurs in yt-dlp's info JSON output, which may be used by external tools. As a result, the downloader or external tool may indiscriminately send cookies with requests to domains or paths for which the cookies are not scoped.

An example of a potential attack scenario exploiting this vulnerability:

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 to a target URL.
yt-dlp extracts this URL and calculates a Cookie header based on its domain for the file downloader to make its request(s) with.
the download URL redirects to a server controlled by the attacker, to which yt-dlp forwards the user's sensitive cookie information.

Patches

yt-dlp version 2023.07.06 fixes this issue by doing the following:

Remove the Cookie header upon HTTP redirects
Have native downloaders calculate their own Cookie header from the cookiejar
Utilize external downloaders' built-in support for cookies instead of passing them as header arguments
If the external downloader does not have proper cookie support, then disable HTTP redirection (axel only)
Process cookies passed as HTTP headers to limit their scope (--add-header "Cookie:..." is scoped to input URL domain only)
Store cookies in a separate cookies field of the info dict instead of http_headers so as not to lose their scope

Patches for youtube-dl are expected and we will update this advisory when they are merged.

Workarounds

It is recommended to upgrade yt-dlp to version 2023.07.06 as soon as possible.

For users who are not able to upgrade:

Avoid using cookies and user authentication methods (--cookies, --cookies-from-browser, --username, --password, --netrc). While extractors may set custom cookies, these usually do not contain sensitive information.
Avoid using --load-info-json

Or, if authentication is a must:

Verify the integrity of download links from unknown sources in browser (including redirects) before passing them to yt-dlp
Use curl as external downloader, since it is not impacted (--downloader curl)
Avoid fragmented formats such as HLS/m3u8, DASH/mpd and ISM (use -f "(bv*+ba/b)[protocol~='^https?$']")

References

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`yt-dlp`	all versions	2023.7.06`pip install --upgrade 'yt-dlp==2023.7.06'`

Affected Products

4 products · 6 configurations

fedorafedoraproject

2 versions

3738

Application

youtube-dlcyoutube-dlc_project

all

Application

youtube-dlyt-dl

≥ 2015.01.25

range

Application

yt-dlpyt-dlp_project

< 2023.07.06.185519

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for yt-dlp, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update yt-dlp to 2023.7.06 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v8mc-9377-rwjj is resolved across your whole dependency graph.
Workarounds
Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Frequently Asked Questions

### Impact During file downloads, yt-dlp or the external downloaders that yt-dlp employs may leak cookies on HTTP redirects to a different host, or leak them when the host for download fragments differs from their parent manifest's host. This vulnerable behavior is present in all versions of [youtube-dl](https://github.com/ytdl-org/youtube-dl), [youtube-dlc](https://github.com/blackjack4494/yt-dlc) and [yt-dlp](https://github.com/yt-dlp/yt-dlp) released since 2015.01.25. All native and external downloaders are affected, except for `curl` and `httpie` (httpie version 3.1.0 or later). At the f

O3 Security · Impact-Aware SCA

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