* 🐛 Block IPv6 transition addresses in SSRF guard
The outbound HTTP SSRF blocklist did not classify NAT64
(64:ff9b::/96), 6to4 (2002::/16) or Teredo (2001:0000::/32)
addresses, whose embedded IPv4 target is invisible to the JVM
InetAddress predicates, so URLs resolving to them could reach cloud
metadata, loopback or RFC 1918 hosts from webhook delivery and media
import.
Transition ranges are now rejected outright and any embedded IPv4 is
re-checked against the full blocklist, including operator-supplied
extra blocked CIDRs.
Closes#11319
* ♻️ Remove dead embedded-IPv4 re-check from SSRF guard
The previous commit added a recursive re-check of the IPv4 embedded in
NAT64/6to4/Teredo addresses, but the `or` in `blocked-address?`
short-circuits on the truthy keyword returned by `transition-prefix`,
so the embedded-IPv4 branch was unreachable. The transition ranges are
already rejected outright (fail-closed), making the re-check both
unnecessary and untested.
Remove `transition-embedded-ipv4`, simplify the IPv6 branch to a plain
prefix check, and correct the docstrings and tests to match what the
code actually does.
AI-assisted-by: glm-5.3-flash
326d83e780