CVE-2025-14523

Publication date 11 December 2025

Last updated 13 January 2026

Ubuntu priority

Cvss 3 Severity Score

Description

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libsoup2.4	25.10 questing	Vulnerable, fix deferred
	25.04 plucky	Ignored end of life, was deferred [2026-01-13]
	24.04 LTS noble	Vulnerable, fix deferred
	22.04 LTS jammy	Vulnerable, fix deferred
	20.04 LTS focal	Vulnerable, fix deferred
	18.04 LTS bionic	Vulnerable, fix deferred
	16.04 LTS xenial	Vulnerable, fix deferred
libsoup3	25.10 questing	Vulnerable, fix deferred
	25.04 plucky	Ignored end of life, was deferred [2026-01-13]
	24.04 LTS noble	Vulnerable, fix deferred
	22.04 LTS jammy	Vulnerable, fix deferred

Notes

hlibk

As of 2026-01-13, the upstream PR fixing this issue has not yet been merged.

Severity score breakdown

Parameter	Value
Base score	8.2 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	Low
Integrity impact	High
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N