CVE-2020-25697

Publication date 26 May 2021

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

A privilege escalation flaw was found in the Xorg-x11-server due to a lack of authentication for X11 clients. This flaw allows an attacker to take control of an X application by impersonating the server it is expecting to connect to.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libx11	22.04 LTS jammy	Ignored
	21.10 impish	Ignored
	21.04 hirsute	Ignored
	20.10 groovy	Ignored
	20.04 LTS focal	Ignored
	18.04 LTS bionic	Ignored
	16.04 LTS xenial	Ignored end of standard support, was deferred
	14.04 LTS trusty	Ignored end of standard support

Notes

mdeslaur

as of 2021-05-19, there is no upstream fix for this issue. This is a long-standing X11 design limitation and is difficult to exploit. We will not be releasing updates for this issue.

Severity score breakdown

CVSS version: CVSS v3.0

Base score 7.0 · High

Base metrics

Parameter	Value
Attack vector	Local
Attack complexity	High
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality impact	High
Integrity impact	High
Availability impact	High

Scores

Parameter	Value
Base score	7.0 · High
Exploitability score	-
Impact score	-

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