Pre-fix, an authenticated dashboard operator could call:
POST /api/v1/site {domain:"evil.example.com", upstream:"10.0.0.1:80"}
POST /api/v1/site/external {subdomain:"x", externalUrl:"http://192.168.1.5"}
and end up with a Caddy site block that proxies PUBLIC traffic at
evil.example.com to an INTERNAL host. Caddy runs on DNS2 (same
network as the targets), so the SSRF lands.
The pre-fix /site upstream regex /^[a-z0-9.-]+:\d{1,5}$/i only
checked charset — it happily accepted 192.168.1.1:80 and
169.254.169.254:80 (AWS metadata IP). /site/external called
validateURL() without blockPrivate:true, leaving the door wide open.
(1) New helper validateUpstream() in fleet-validation.js — reuses
resolveAndCheckAddress() (DC-068 SSRF work) to reject literal
private IPv4/IPv6 (loopback / RFC1918 / link-local / CGNAT /
multicast / broadcast / 0.0.0.0 / TEST-NET / benchmark ranges),
resolve hostnames and reject private answers (rebinding defense),
and cap port to 1..65535. Opt-in via SITES_ALLOW_PRIVATE_UPSTREAMS=true.
(2) /site calls validateUpstream() BEFORE caddy.modify() — gate
happens before any state mutation. Throws ValidationError with
canonical [DC-074] tag and a redacted hostname audit log entry.
(3) /site/external calls validateURL() (syntax only) + validateUpstream()
(private-IP gate). validateURL's blockPrivate is intentionally
NOT passed because it has no opt-in — that's what validateUpstream
is for.
(4) Tests (__tests__/routes/sites-dc074.routes.test.js, NEW, 60/60
passing): helper unit tests (format, literal IPv4/IPv6 private
reject, public IP accept, hostname resolve + rebinding defense,
env opt-in override), POST /site integration (10 regression
payloads + public accept + opt-in + port range + charset), POST
/site/external integration (8 regression payloads + public
accept + DNS rebinding defense + opt-in), canonical SSRF regression
proof (RFC 1918 literal IPv4 in upstream + RFC 1918 literal IPv4
in URL host), unchanged-behavior checks on isPrivateOrReservedIPv4/IPv6.
Full repo suite: 2402/2402 tests in 102 suites (zero regressions).
GLM-5.3 stand-in judge round 1 (deleg_384b9f53, 41.46s, 3 tool
calls, MiniMax-M3 per Sami authorization 2026-08-17): A ship-first.
Refs: codex-as-judge SKILL.md 'Stand-in fallback chain'. Verdict
record: /root/dashcaddy-polish/.ump-verdicts/2026-08-18T22-35-00Z-dc-074-round-1-A.json
DashCaddy Polish Loop
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