PR #94 only blocked 127.0.0.0/8 (loopback) and 169.254.0.0/16
(link-local/IMDS). An attacker could still register a workspace with
a URL in any RFC-1918 range (10.x, 172.16–31.x, 192.168.x) and
redirect A2A proxy traffic to internal services.
Block all five reserved ranges in validateAgentURL:
- 169.254.0.0/16 link-local (IMDS: AWS/GCP/Azure)
- 127.0.0.0/8 loopback (self-SSRF)
- 10.0.0.0/8 RFC-1918
- 172.16.0.0/12 RFC-1918 (includes Docker bridge networks)
- 192.168.0.0/16 RFC-1918
Agents must use DNS hostnames, not IP literals. The provisioner
still writes 127.0.0.1 URLs via direct SQL UPDATE (CASE guard
preserves those); this blocklist only applies to the /registry/register
request body.
Tests: updated 3 previously-allowed RFC-1918 cases to expect rejection;
added 9 new cases covering range boundaries and the Docker bridge range.
All 22 validateAgentURL subtests pass.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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