Red Hat: CVE-2025-14523: libsoup: libsoup: Duplicate Host Header Handling Causes Host-Parsing Discrepancy (First- vs Last-Value Wins) (Multiple Advisories)

A flaw in libsoup’s HTTP header handling allows multiple Host: headers in a request and returns the last occurrence for server-side processing. Common front proxies often honor the first Host: header, so this mismatch can cause vhost confusion where a proxy routes a request to one backend but the backend interprets it as destined for another host. This discrepancy enables request-smuggling style attacks, cache poisoning, or bypassing host-based access controls when an attacker supplies duplicate Host headers.