The connect-time guard permitted every loopback address so that a locally
configured proxy (proxy: http://127.0.0.1:9050) stayed reachable. But the
connect guard is the only check that media URLs derived from remote metadata
ever face — validate_url sees just the submitted URL — so that blanket
allowance let a remote manifest steer the download subprocess at services
bound to the server's loopback interface, with the response written to the
download directory and served back by the UI.
Permit loopback only at the host:port of a proxy the operator configured,
taken from yt-dlp's proxy option and the *_proxy environment variables.
Nothing is lost: when a proxy is in use yt-dlp hands it the media URL instead
of resolving that URL locally, so the two cases never overlap. Every other
loopback destination now falls under the same is_global policy as the rest.
Reported by m3rl1nu5 (https://github.com/hai135) in GHSA-73g4-qhhq-c32c.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The SSRF guard rejects any address that isn't globally routable, which breaks
proxy/VPN setups that resolve hosts into private or special-use ranges. The
reported case is Fake-IP clients (sing-box, Clash, Mihomo) that map YouTube to
the RFC 2544 benchmarking range 198.18.0.0/15 to tunnel the traffic; MeTube
rejected it with "Refusing to fetch internal address" even though yt-dlp itself
handles it fine.
Add a boolean ALLOW_PRIVATE_ADDRESSES (default false) that, when set, skips both
layers: validate_url returns after scheme validation without the internal-host
checks, and the connect-time socket guard is not installed. Threaded to the
download subprocess via Download so the guard sees it too. Scheme validation
(http/https only) still applies. Documented in the README as a trust-your-network
opt-out that disables SSRF protection.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The connect-time getaddrinfo guard added for redirect/rebinding SSRF covers
only the download subprocess: metadata extraction runs in the main process
(where a process-wide guard would reject the server's own HOST=0.0.0.0 bind),
and native curl_cffi/libcurl resolution used by --impersonate bypasses Python's
socket module. Record both in url_guard's docstring and at the extraction site
so the boundary is explicit; network isolation remains the backstop.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
validate_url only inspects the submitted URL string. yt-dlp then follows HTTP
redirects and resolves media URLs from remote metadata without re-checking, so
an allowed URL that 302s to http://169.254.169.254/ (cloud metadata) or an
RFC1918 host is still fetched — the guard's own docstring scoped this out.
Install a getaddrinfo guard in the download subprocess that re-validates every
resolved address at actual connect time, covering redirects and DNS rebinding
for any backend resolving through Python's socket module (urllib, requests).
Loopback is permitted so locally-configured proxies keep working; link-local,
RFC1918 and unique-local are blocked. Native resolvers (curl_cffi/libcurl via
--impersonate) bypass this and rely on network isolation as the backstop.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
validate_url() previously returned None (allow) on socket.gaierror, so a
host that failed to resolve at check time was passed straight to yt-dlp. A
host we cannot resolve is a host we cannot verify as non-internal, and it may
resolve differently when yt-dlp fetches it. Reject it instead.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
User-submitted URLs were passed straight to yt-dlp's generic extractor,
letting the server fetch internal endpoints (cloud metadata, loopback,
RFC1918 hosts). Add a url_guard.validate_url check at every URL ingress
(add, subscribe, and nested playlist recursion) that rejects non-http(s)
schemes and hosts resolving to non-global addresses, while leaving bare
video IDs and search prefixes untouched.
Alex Shnitman