Quick answers
- Is CVE-2026-109966 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-109966 being exploited in the wild.
- How severe is CVE-2026-109966?
- Medium severity, with a CVSS score of 5.3, published 13 October 2026.
- Which products and versions are affected?
- Marcopiovanello Yt-Dlp-Web-Ui through 4.0.0.
- Is there a fix for CVE-2026-109966?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-109966 attacked?
- It is attacked over the network, in a web application.
- Am I affected by CVE-2026-109966?
- Check whether you run Marcopiovanello Yt-Dlp-Web-Ui at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is an argument injection flaw in the JSON-RPC endpoint where URL parameters prefixed with dashes (e.g., --load-info-json) are passed unsanitized to the underlying yt-dlp command execution. An attacker can craft malicious requests to /rpc/http or /rpc/ws with dash-prefixed parameters that cause yt-dlp to load and process attacker-specified JSON files from the server filesystem, with the contents reflected in responses. The flaw is accessible without authentication.
Affected products
- marcopiovanello yt-dlp-web-ui through 4.0.0
Timeline
- 2026-10-13: disclosed