# CVE-2026-109967: yt-dlp-web-ui NULL pointer dereference in Service.Formats method

Source: https://junglewise.ai/threats/cve-2026-109967-yt-dlp-web-ui-through-4-0-0-contains-a-null-pointer-dereference  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-109967 · Severity: high · CVSS 7.5 · Published 2026-10-13

yt-dlp-web-ui is a self-hosted web interface and RPC server for the yt-dlp video downloader. A remote attacker can crash the server by sending a specially crafted request with an invalid URL parameter to the Service.Formats JSON-RPC method, causing a denial of service with no authentication required.

Technologies: [Marcopiovanello Yt-Dlp-Web-Ui](https://junglewise.ai/threats/technologies/yt-dlp-web-ui). Vendors: [Marcopiovanello](https://junglewise.ai/threats/vendors/marcopiovanello).

## Quick answers

**Is CVE-2026-109967 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-109967 being exploited in the wild.

**How severe is CVE-2026-109967?** High severity, with a CVSS score of 7.5, 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-2026-109967?** 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-2026-109967 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-109967?** 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 a NULL pointer dereference in the Service.Formats JSON-RPC method caused by insufficient input validation. When a malicious URL like "--version" is passed to the ParseURL function, yt-dlp produces invalid JSON output that fails to unmarshal properly; the code does not check for unmarshaling errors before dereferencing pointers, causing an unrecovered panic that terminates the process. This is remotely exploitable without authentication via network-based JSON-RPC calls.

## Affected products

- marcopiovanello yt-dlp-web-ui through 4.0.0

## Timeline

- 2026-10-13: disclosed

## References

- [https://github.com/marcopiovanello/yt-dlp-web-ui](https://github.com/marcopiovanello/yt-dlp-web-ui)
- [https://github.com/marcopiovanello/yt-dlp-web-ui/blob/v4.0.0/server/formats/parser.go](https://github.com/marcopiovanello/yt-dlp-web-ui/blob/v4.0.0/server/formats/parser.go)

## Related threats

- [yt-dlp-web-ui argument injection in JSON-RPC methods](https://junglewise.ai/threats/cve-2026-109966-yt-dlp-web-ui-through-4-0-0-contains-an-argument-injection)
- [marcopiovanello yt-dlp-web-ui command injection in NewGenericDownload](https://junglewise.ai/threats/cve-2026-93371-marcopiovanello-yt-dlp-web-ui-command-injection-in)