---
id: CVE-2025-14523
title: >-
  A flaw in libsoup’s HTTP header handling allows multiple Host: headers in a
  request and returns the last occurrence for server-side processing
summary: >-
  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 con…
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N'
cwe:
  - CWE-444
published: '2025-12-11'
updated: '2026-06-25'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-14523'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:0421'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0422'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0423'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0836'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0867'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0868'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0905'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0906'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0907'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0908'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0909'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0911'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:0925'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:1509'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:1569'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:1570'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:1571'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:1572'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2025-14523'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2421349'
    label: secalert@redhat.com
  - url: 'https://gitlab.gnome.org/GNOME/libsoup/-/issues/472'
    label: secalert@redhat.com
tags:
  - nvd
epss: 0.00544
epssPercentile: 0.44566
ingestedAt: '2026-06-29T13:24:34.621Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.