"is_global_address" in ""src/pyload/core/utils/web/check.py"" (https://github.com/pyload/pyload/blob/1b12dc7f348db8c144e0f39215680415e90ca4d2/src/pyload/core/utils/web/check.py) is the central guard against SSRF-style outbound connections in pyload-ng. It tests whether a given IP is "globally routable" via Python's "ipaddress.ip_address(value).is_global", and callers treat "not is_global" as "deny": Python's "ipaddress.IPv6Address.is_global" classifies the NAT64 well-known prefix as globally routable on every supported Python version (3.9 through 3.14 confirmed), and on older Pythons (3.9-3.11) the 6to4 prefix as well: | address | "is_global" on Py 3.9-3.11 | "is_global" on Py 3.12+ | wrapped IPv4 | |----------------------------------|---------------------------|--------------------------|----------------------| | "2002:7f00:0001::" (6to4) | True | False | 127.0.0.1 | | "2002:0a00:0001::" (6to4) | True | False | 10.0.0.1 | | "2002:a9fe:a9fe::" (6to4) | True | False | 169.254.169.254 (IMDS)| | "64:ff9b::a9fe:a9fe" (NAT64) | True | True | 169.254.169.254 | | "64:ff9b::7f00:1" (NAT64) | True | True | 127.0.0.1 | pyload-ng declares "python_requires = >=3.9" ("setup.cfg"), so deployments on Python 3.9-3.11 see the 6to4 path too. The NAT64 path is universal. "is_global" returns True for these wrappers, so "is_global_address" returns True and the deny check passes. The pycurl "PREREQFUNC" at ""src/pyload/core/network/http/http_request.py:680"" (https://github.com/pyload/pyload/blob/1b12dc7f348db8c144e0f39215680415e90ca4d2/src/pyload/core/network/http/http_request.py#L680) consults the same helper just before TCP-connect: On a host with 6to4 routing (legacy operator tunnels; "2002::/16" still configurable) or NAT64 (cloud IPv6-only subnets with NAT64 gateway), the encoded form routes to the embedded IPv4 and the curl connection terminates at the internal endpoint, defeating the deny. "is_global_host" (the helper that callers like "parse_urls" use against a URL hostname) feeds through "host_to_ip" which pins "family=AF_INET", so hostname-based reach to these forms relies on the attacker supplying an IPv6 literal in the URL — but the curl PREREQFUNC sees the actual resolved IP (the AAAA returned for the hostname), so a hostname with an AAAA record set to one of the bypass forms reaches the same gap. Cross-reference: this is the same incomplete-coverage class as pydantic-ai's "GHSA-cqp8-fcvh-x7r3" (https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-cqp8-fcvh-x7r3) / CVE-2026-46678. pyload-ng's prior SSRF advisories "GHSA-7gvf-3w72-p2pg" (https://github.com/pyload/pyload/security/advisories/GHSA-7gvf-3w72-p2pg) and "GHSA-8rp3-xc6w-5qp5" (https://github.com/pyload/pyload/security/advisories/GHSA-8rp3-xc6w-5qp5) both went through "is_global_host" / "is_global_address"; the IPv6 transition gap is orthogonal to those redirect-bypass classes.