Description
An issue was discovered in XListExtensions in ListExt.c in libX11 through 1.6.5. A malicious server can send a reply in which the first string overflows, causing a variable to be set to NULL that will be freed later on, leading to DoS (segmentation fault).
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libx11 | 2:1.6.6-1 | — |
| Debian 13 | libx11 | 2:1.6.6-1 | — |
| Debian 12 | libx11 | 2:1.6.6-1 | — |
| Debian 8 | libx11 | 2:1.6.2-3+deb8u2 | DLA-1482-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | libx11 | 2:1.6.4-3ubuntu0.1 | USN-3758-1 |
| Ubuntu 16.04 LTS | libx11 | 2:1.6.3-1ubuntu2.1 | USN-3758-1 |
| Ubuntu 14.04 LTS | libx11 | 2:1.6.2-1ubuntu2.1 | USN-3758-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | gdm +2 | 1:3.28.2-16.el7 | RHSA-2019:2079 |
| RHEL 7 | libX11 +2 | 1.6.7-2.el7 | RHSA-2019:2079 |
| RHEL 7 | libxkbcommon +3 | 0.7.1-3.el7 | RHSA-2019:2079 |
| RHEL 7 | mesa-libGLw +1 | 8.0.0-5.el7 | RHSA-2019:2079 |
| RHEL 7 | xorg-x11-drv-ati | 19.0.1-2.el7 | RHSA-2019:2079 |
| RHEL 7 | xorg-x11-drv-vesa | 2.4.0-3.el7 | RHSA-2019:2079 |
| RHEL 7 | xorg-x11-drv-wacom +1 | 0.36.1-3.el7 | RHSA-2019:2079 |
| RHEL 7 | xorg-x11-server +9 | 1.20.4-7.el7 | RHSA-2019:2079 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 | libX11 | 1.6.5-3.3.1 | SUSE-SU-2018:2955-1 |
| SLES 12 SP3 | libX11 | 1.6.2-12.5.1 | SUSE-SU-2018:3102-1 |
| SLES 12 SP3 | libxcb | 1.10-4.3.1 | SUSE-SU-2018:3102-1 |
| SLES 11 SP4 | xorg-x11-libX11 | 7.4-5.11.72.9.1 | SUSE-SU-2018:2934-1 |
| SLES 11 SP3 | xorg-x11-libX11 | 7.4-5.11.72.9.1 | SUSE-SU-2018:2934-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 SP3 | libX11 | 1.6.2-12.5.1 | SUSE-SU-2018:3102-1 |
| SLES for SAP 12 SP3 | libxcb | 1.10-4.3.1 | SUSE-SU-2018:3102-1 |
| SLES for SAP 11 SP4 | xorg-x11-libX11 | 7.4-5.11.72.9.1 | SUSE-SU-2018:2934-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | xorg-x11-libX11 | 7.4-5.11.72.9.1 | SUSE-SU-2018:2934-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | libX11 | 1.7.2-1.2 | openSUSE-SU-2024:10918-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | libx11 | 1.6.6-r0 | — |
| Alpine v3.23 | libx11 | 1.6.6-r0 | — |
| Alpine v3.22 | libx11 | 1.6.6-r0 | — |
| Alpine v3.21 | libx11 | 1.6.6-r0 | — |
| Alpine v3.20 | libx11 | 1.6.6-r0 | — |
Show 15 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | libx11 | 1.6.6-r0 | — |
| Alpine v3.18 | libx11 | 1.6.6-r0 | — |
| Alpine v3.17 | libx11 | 1.6.6-r0 | — |
| Alpine v3.16 | libx11 | 1.6.6-r0 | — |
| Alpine v3.15 | libx11 | 1.6.6-r0 | — |
| Alpine v3.14 | libx11 | 1.6.6-r0 | — |
| Alpine v3.13 | libx11 | 1.6.6-r0 | — |
| Alpine v3.12 | libx11 | 1.6.6-r0 | — |
| Alpine v3.11 | libx11 | 1.6.6-r0 | — |
| Alpine v3.10 | libx11 | 1.6.6-r0 | — |
| Alpine v3.9 | libx11 | 1.6.6-r0 | — |
| Alpine v3.8 | libx11 | 1.6.6-r0 | — |
| Alpine v3.7 | libx11 | 1.6.6-r0 | — |
| Alpine v3.6 | libx11 | 1.6.6-r0 | — |
| Alpine v3.5 | libx11 | 1.6.6-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | libX11 +2 | 1.6.5-2.amzn2.0.2 | ALAS2-2019-1226 |
| Amazon Linux 2 | xorg-x11-server-Xdmx +8 | 1.20.4-7.amzn2.0.1 | ALAS2-2020-1433 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | gdm +2 | 1:3.28.2-16.el7 | ELSA-2019-2079 |
| Oracle Linux 7 | libX11 +2 | 1.6.7-2.el7 | ELSA-2019-2079 |
| Oracle Linux 7 | libxkbcommon +3 | 0.7.1-3.el7 | ELSA-2019-2079 |
| Oracle Linux 7 | mesa-libGLw +1 | 8.0.0-5.el7 | ELSA-2019-2079 |
| Oracle Linux 7 | xorg-x11-drv-ati | 19.0.1-2.el7 | ELSA-2019-2079 |
| Oracle Linux 7 | xorg-x11-drv-vesa | 2.4.0-3.el7 | ELSA-2019-2079 |
| Oracle Linux 7 | xorg-x11-drv-wacom +1 | 0.36.1-3.el7 | ELSA-2019-2079 |
| Oracle Linux 7 | xorg-x11-server-Xdmx +8 | 1.20.4-7.el7 | ELSA-2019-2079 |
Advisories 10
- RHSA-2019:2079 Red Hat Security Advisory: Xorg security and bug fix update Red Hat Security Advisories (RHSA) · Jun 30, 2026
- USN-3758-1 libx11 vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-1482-1 libx11 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10918-1 libX11-6-1.7.2-1.2 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:2955-1 Security update for libX11 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:2934-1 Security update for xorg-x11-libX11 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:3102-1 Security update for libX11 and libxcb SUSE / openSUSE Security Updates · May 2, 2025
- ALAS2-2020-1433 Moderate: xorg-x11-server security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jun 3, 2020
- ELSA-2019-2079 Moderate: Xorg security and bug fix update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Aug 13, 2019
- ALAS2-2019-1226 Moderate: libX11 security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jun 13, 2019
References
- USN-3758-2 vendor-advisory
- https://bugzilla.suse.com/show_bug.cgi?id=1102073
- GLSA-201811-01 vendor-advisory
- 105177 vdb-entry
- https://cgit.freedesktop.org/xorg/lib/libX11/commit/?id=e83722768fd5c467ef61fa159e8c6278770b45c2
- [oss-security] 20180821 X.Org security advisory: August 21, 2018 mailing-list
- 1041543 vdb-entry
- [debian-lts-announce] 20180829 [SECURITY] [DLA 1482-1] libx11 security update mailing-list
- [xorg-announce] 20180821 libX11 1.6.6 mailing-list
- USN-3758-1 vendor-advisory
- FEDORA-2019-6a756fe3a5 vendor-advisory
- RHSA-2019:2079 vendor-advisory