From 9ef3ade40261692d3f2bc318caaf963c2cf21895 Mon Sep 17 00:00:00 2001
From: Shirshendu Bhowmick
 <12836504+shirshendubhowmick@users.noreply.github.com>
Date: Sat, 9 May 2026 13:38:45 +0530
Subject: [PATCH] fix(context): return empty string for invalid remote IP in
 ClientIP method

fix(gin): unmap address before checking if it is IPv4 in prepareTrustedCIDRs
---
 context.go | 3 +++
 gin.go     | 2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/context.go b/context.go
index 3ecaf520..768aa462 100644
--- a/context.go
+++ b/context.go
@@ -1022,6 +1022,9 @@ func (c *Context) ClientIP() string {
 			}
 		}
 	}
+	if !remoteIP.IsValid() {
+		return ""
+	}
 	return remoteIP.String()
 }
 
diff --git a/gin.go b/gin.go
index cdb102b5..d01f344a 100644
--- a/gin.go
+++ b/gin.go
@@ -418,7 +418,7 @@ func (engine *Engine) prepareTrustedCIDRs() ([]netip.Prefix, error) {
 			if err != nil {
 				return cidrs, &net.ParseError{Type: "IP address", Text: trustedProxy}
 			}
-			if addr.Is4() {
+			if addr.Unmap().Is4() {
 				trustedProxy += "/32"
 			} else {
 				trustedProxy += "/128"