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CVE-2026-46415 — Vulnerability in pkg.jsn.cam/caddy-defender — CVE...

HIGH

Caddy Defender trusted proxy client IP bypass

Published May 19, 2026Updated June 25, 2026Source: osv

Summary

### 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 `client_ip` request variable after applying the configured `trusted_proxies` 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. ### Patches The issue is fixed by making Defender prefer Caddys resolved `client_ip` request variable when it is available. Defender falls back to `RemoteAddr` only when Caddy has not provided a resolved client IP. Users should upgrade to `v0.10.1` or later. ### Workarounds There is no complete workaround in affected Defender versions for deployments that rely on Caddys trusted proxy client IP resolution. Until upgrading, affected users should enforce equivalent IP blocking at the trusted proxy, CDN, load balancer, firewall, or other edge layer before traffic reaches Caddy. Deployments where Caddy receives traffic directly from clients, without an intermediate trusted proxy, are not affected by this bypass.

Advisory Timeline

  • First published May 19, 2026 (146 days ago).
  • Last revised June 25, 2026 — 37 days after initial publication.

Remediation

Upgrade to the fixed version using your package manager.

Go
Update pkg.jsn.cam/caddy-defender to 0.10.1 or later
go get pkg.jsn.cam/caddy-defender@v0.10.1

After upgrading, run your dependency scanner again to confirm the vulnerability is resolved.

Affected Packages (1)

Affects 1 ecosystem: go (1).

PackageEcosystemAffectedFixed In
pkg.jsn.cam/caddy-defender
go
All versions0.10.1

Vulnerability Classification

Common Weakness Enumeration (CWE) identifiers for this vulnerability type.

CVSS Score Breakdown

What the CVSS (Common Vulnerability Scoring System) 8.2 score means for each attack dimension.

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N

Frequently Asked Questions

What is CVE-2026-46415?
Caddy Defender trusted proxy client IP bypass This vulnerability has been assigned a severity rating of HIGH (CVSS score: 8.2/10).
How do I check if my project is affected by CVE-2026-46415?
CVE-2026-46415 affects pkg.jsn.cam/caddy-defender. Use GeekWala's free vulnerability scanner to check your dependencies against CVE-2026-46415 and 200,000+ other known vulnerabilities.

Severity & Exploitability

CVSS Score
8.2

High exploitability or significant impact. Prioritize remediation within days.

Also Known As

GHSA-3h23-rrpc-3p87
GO-2026-5086

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