CVE-2025-14523 HIGH

CVE-2025-14523: Libsoup: libsoup: duplicate host header handling causes host-parsing discrepancy (first- vs last-value wins)

Vendor Red Hat
Product Red Hat Enterprise Linux 6
Weakness CWE-444
Published December 11, 2025
Last update March 19, 2026

CVSS base score

8.2/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality Low
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

December 11, 2025 CVE published
March 19, 2026 Record updated