CVE-2025-14523 — Libsoup: libsoup: duplicate host header handling causes host-parsing discrepancy (first- vs last-value wins)
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 …
Published: 2025-12-11 · CVSS: 8.2 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7