CVE-2025-4035

Publication date 29 April 2025

Last updated 24 September 2025

Ubuntu priority

Cvss 3 Severity Score

Description

A flaw was found in libsoup. When handling cookies, libsoup clients mistakenly allow cookies to be set for public suffix domains if the domain contains at least two components and includes an uppercase character. This bypasses public suffix protections and could allow a malicious website to set cookies for domains it does not own, potentially leading to integrity issues such as session fixation.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libsoup3	25.10 questing	Vulnerable, fix deferred
	25.04 plucky	Vulnerable, fix deferred
	24.10 oracular	Ignored end of life, was deferred [2025-09-23]
	24.04 LTS noble	Vulnerable, fix deferred
	22.04 LTS jammy	Vulnerable, fix deferred
	20.04 LTS focal	Not in release
libsoup2.4	25.10 questing	Vulnerable, fix deferred
	25.04 plucky	Vulnerable, fix deferred
	24.10 oracular	Ignored end of life, was deferred [2025-07-28]
	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

Notes

hlibk

Upstream PR with the fix has not been merged yet as of 2025-09-23.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
libsoup3	Upstream: https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/448

Severity score breakdown

Parameter	Value
Base score	4.3 · Medium
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	Required
Scope	Unchanged
Confidentiality	None
Integrity impact	Low
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N