CVE-2026-109966: yt-dlp-web-ui through 4.0.0 Argument Injection via Service.Formats JSON-RPC Method

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-13 · updated 2026-10-26
Weakness: CWE-88

Description

yt-dlp-web-ui through 4.0.0 contains an argument injection vulnerability that allows unauthenticated remote attackers to inject yt-dlp options by supplying a dash-prefixed url parameter to the Service.Formats JSON-RPC method. Attackers can send values like --load-info-json via /rpc/http or /rpc/ws to make yt-dlp load attacker-chosen JSON files from the server filesystem, with contents reflected in responses.

Affected products

marcopiovanello yt-dlp-web-ui: through 4.0.0

References

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/vazzzy071-crypto/security-advisories/blob/main/advisories/2026-10-marcopiovanello-yt-dlp-web-ui-rpc-arg-injection.md
https://www.vulncheck.com/advisories/yt-dlp-web-ui-through-4.0.0-argument-injection-via-service-formats-json-rpc-method

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