Caddy Defender trusted proxy client IP bypass
Published Jul 20, 2026 · Updated Nov 3, 2026
Original summary
Normalized public record · Updated Nov 3, 2026
Caddy Defender trusted proxy client IP bypass
Publisher and source text is retained separately from QFinch interpretation.
QFinch assessment
Caddy Defender used `r.RemoteAddr` when evaluating whether a request should be blocked. `RemoteAddr` is the address of the immediate peer connected to Caddy.
Potential impact
Caddy Defender used r.RemoteAddr when evaluating whether a request should be blocked. RemoteAddr is the address of the immediate peer connected to Caddy. In deployments where Caddy is behind a trusted proxy, CDN, or load balancer, the immediate peer is usually the proxy, not the original client. Caddy resolves the original client address into its clientip request variable after applying the configured trustedproxies policy, but Defender did not use that value. As a result, clients from blocked IP ranges could bypass Defender when accessing Caddy through a trusted proxy whose own IP address was not blocked. This affects deployments that use Defender behind trusted proxies and expect it to enforce blocking based on the real client IP.
Evidence: public source recordsAffected products
| Affected package, product or range | Fix status |
|---|---|
| Consult the referenced vendor advisory for affected versions. | Consult source advisory |
Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.
Remediation
Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.
- Confirm the affected product and reachable code path exist in your environment.
- Apply the vendor-supported patch or mitigation from the primary advisory.
- Rescan the exact deployed revision and retain verification evidence.
Evidence coverage
- SSVC priority
- MEDIUM
- Confidence
- Not available
- Aliases
- None reported
Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.
Sources and record history
Record history
Published Jul 20, 2026 · Last refreshed Nov 3, 2026