Skip to content
Fencer Vulns
high 7.8

CVE-2021-3472 json

A flaw was found in xorg-x11-server in versions before 1.20.11.

published 2021-04-26 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-26794

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.1%
EPSS 1.1% chance of exploitation in 30 days, percentile 64%
public exploits
0
none known

Summary

A flaw was found in xorg-x11-server in versions before 1.20.11. An integer underflow can occur in xserver which can lead to a local privilege escalation. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Patch / fix

  • x.org x_server 1.20.11
  • xorg-server Debian 14, Debian 13, Debian 12 2:1.20.11-1

debian advisories DEBIAN-CVE-2021-3472

  • xorg-server Ubuntu 16.04 LTS 2:1.18.4-0ubuntu0.12
  • xorg-server Ubuntu 18.04 LTS 2:1.19.6-1ubuntu4.9
  • xorg-server Ubuntu 20.04 LTS 2:1.20.9-2ubuntu1.2~20.04.2
  • xorg-server-hwe-16.04 Ubuntu 16.04 LTS 2:1.19.6-1ubuntu4.1~16.04.6
  • xorg-server-hwe-18.04 Ubuntu 18.04 LTS 2:1.20.8-2ubuntu2.2~18.04.5
  • xorg-server Ubuntu Pro 14.04 LTS 2:1.15.1-0ubuntu2.11+esm4

ubuntu advisories UBUNTU-CVE-2021-3472

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • xorg-x11-server RHEL 7 1.20.4-16.el7_9
  • xorg-x11-server-Xdmx RHEL 7 1.20.4-16.el7_9
  • xorg-x11-server-Xorg RHEL 7 1.20.4-16.el7_9
  • xorg-x11-server-Xvfb RHEL 7 1.20.4-16.el7_9
  • xorg-x11-server-Xnest RHEL 7 1.20.4-16.el7_9
  • xorg-x11-server-common RHEL 7 1.20.4-16.el7_9
  • xorg-x11-server-source RHEL 7 1.20.4-16.el7_9
  • xorg-x11-server-Xephyr RHEL 7 1.20.4-16.el7_9

red hat advisories RHSA-2021:2033

  • xorg-x11-server SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLES 15 SP1-BCL +6 more 1.20.3-14.5.16.1
  • xorg-x11-server SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 7.6_1.18.3-76.40.1
  • xorg-x11-server SLE Workstation Extension 15 SP2, SLE Module for Development Tools 15 SP2, SLE Module for Basesystem 15 SP2 1.20.3-22.5.25.1
  • xorg-x11-server SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 1.19.6-10.23.1
  • xorg-x11-server SLES for SAP 12 SP4, SLES 12 SP4-LTSS, OpenStack Cloud Crowbar 9 +1 more 1.19.6-4.22.1
  • xorg-x11-server SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 1.19.6-8.30.1
  • xorg-x11-server SLES 11 SP4-LTSS, SLE Point of Sale 11 SP3 7.4-27.122.40.1

suse advisories SUSE-SU-2021:1188-1SUSE-SU-2021:1187-1SUSE-SU-2021:1182-1SUSE-SU-2021:1181-1SUSE-SU-2021:1180-1SUSE-SU-2021:1179-1

  • xorg-x11-server openSUSE Tumbleweed 1.20.13-1.2
  • xwayland openSUSE Tumbleweed 21.1.2-2.1
  • xorg-x11-server openSUSE Leap 15.2 1.20.3-lp152.8.21.1

opensuse advisories openSUSE-SU-2024:11525-1openSUSE-SU-2024:11528-1openSUSE-SU-2021:0554-1

  • xwayland Alpine 3.24, Alpine 3.23, Alpine 3.22 +8 more 21.1.0-r4
  • xorg-server Alpine 3.10 1.20.5-r3
  • xorg-server Alpine 3.11 1.20.6-r3
  • xorg-server Alpine 3.13, Alpine 3.12 1.20.10-r1
  • xorg-server Alpine 3.24, Alpine 3.23, Alpine 3.22 +8 more 1.20.10-r5

alpine advisories ALPINE-CVE-2021-3472

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • xorg-server Arch Linux 1.20.11-1
  • xorg-xwayland Arch Linux 21.1.1-1

arch linux advisories AVG-1811AVG-1812

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-3472 updated cvss 7.8

xorg-x11-server: XChangeFeedbackControl integer underflow leads to privilege escalation

  • Red Hat Enterprise Linux 6 xorg-x11-server, xorg-x11-server-Xdmx, xorg-x11-server-Xorg, xorg-x11-server-Xvfb, xorg-x11-server-Xnest, xorg-x11-server-common, +2 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 xorg-x11-server, xorg-x11-server-Xdmx, xorg-x11-server-Xorg, xorg-x11-server-Xvfb, xorg-x11-server-Xnest, xorg-x11-server-common, +3 more
    affected: no fix available
  • Red Hat Enterprise Linux Client (v. 7) xorg-x11-server 1.20.4-16.el7_9, xorg-x11-server-Xorg 1.20.4-16.el7_9, xorg-x11-server-common 1.20.4-16.el7_9, xorg-x11-server-Xephyr 1.20.4-16.el7_9 Red Hat Enterprise Linux Client Optional (v. 7) xorg-x11-server-Xdmx 1.20.4-16.el7_9, xorg-x11-server-Xvfb 1.20.4-16.el7_9, xorg-x11-server-Xnest 1.20.4-16.el7_9, xorg-x11-server-source 1.20.4-16.el7_9, xorg-x11-server-Xwayland 1.20.4-16.el7_9 Red Hat Enterprise Linux ComputeNode Optional (v. 7) xorg-x11-server 1.20.4-16.el7_9, xorg-x11-server-Xdmx 1.20.4-16.el7_9, xorg-x11-server-Xorg 1.20.4-16.el7_9, xorg-x11-server-Xvfb 1.20.4-16.el7_9, xorg-x11-server-Xnest 1.20.4-16.el7_9, xorg-x11-server-common 1.20.4-16.el7_9, +3 more Red Hat Enterprise Linux Server (v. 7) xorg-x11-server 1.20.4-16.el7_9, xorg-x11-server-Xorg 1.20.4-16.el7_9, xorg-x11-server-common 1.20.4-16.el7_9, xorg-x11-server-Xephyr 1.20.4-16.el7_9 Red Hat Enterprise Linux Server Optional (v. 7) xorg-x11-server-Xdmx 1.20.4-16.el7_9, xorg-x11-server-Xvfb 1.20.4-16.el7_9, xorg-x11-server-Xnest 1.20.4-16.el7_9, xorg-x11-server-source 1.20.4-16.el7_9, xorg-x11-server-Xwayland 1.20.4-16.el7_9 Red Hat Enterprise Linux Workstation (v. 7) xorg-x11-server 1.20.4-16.el7_9, xorg-x11-server-Xorg 1.20.4-16.el7_9, xorg-x11-server-common 1.20.4-16.el7_9, xorg-x11-server-Xephyr 1.20.4-16.el7_9
    +1 more products
    Red Hat Enterprise Linux Workstation Optional (v. 7) xorg-x11-server-Xdmx 1.20.4-16.el7_9, xorg-x11-server-Xvfb 1.20.4-16.el7_9, xorg-x11-server-Xnest 1.20.4-16.el7_9, xorg-x11-server-source 1.20.4-16.el7_9, xorg-x11-server-Xwayland 1.20.4-16.el7_9
    fixed: vendor fix RHSA-2021:2033
  • Red Hat Enterprise Linux 9 xorg-x11-server, xorg-x11-server-Xdmx, xorg-x11-server-Xorg, xorg-x11-server-Xvfb, xorg-x11-server-Xnest, xorg-x11-server-common, +2 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.05% chance of exploitation in the next 30 days, higher than 64% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.2 AV:L/AC:L/Au:N/C:C/I:C/A:C

Affected products

  • n/a xorg-x11-server

Classification

Weakness
  • CWE-191 Integer Underflow (Wrap or Wraparound)

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.