ALSA-2026:89730: Important: libX11 security update

Q: Who is exposed to this issue?

Systems with the affected AlmaLinux libX11 packages installed are potentially exposed when an application using libX11 connects to a malicious X server.

Q: What does an attacker need to exploit the vulnerability?

The attacker needs to provide or control a malicious X server that a libX11-using client connects to. The available advisory data does not describe additional prerequisites or attack vectors.

Q: How can I determine whether a system needs remediation?

Check whether the system has installed packages from the affected set: libX11, libX11-common, libX11-devel, or libX11-xcb. Compare installed package updates against the ALSA-2026:89730 security update.

Published Oct 26, 2026

Updated

The libX11 packages contain the core X11 protocol client library.

Security Fix(es):

libX11: libX11: Heap-based buffer overflow via malicious X server (CVE-2026-88806)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Affected Software

4 affected componentsFixes available

almalinux/libx11<1.6.8-10.el8_10

1.6.8-10.el8_10

almalinux/libx11-common<1.6.8-10.el8_10

1.6.8-10.el8_10

almalinux/libx11-devel<1.6.8-10.el8_10

1.6.8-10.el8_10

almalinux/libx11-xcb<1.6.8-10.el8_10

1.6.8-10.el8_10

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade almalinux/libX11 to a version that resolves this vulnerability.
Fixed in 1.6.8-10.el8_10
Upgrade
Upgrade almalinux/libX11-common to a version that resolves this vulnerability.
Fixed in 1.6.8-10.el8_10
Upgrade
Upgrade almalinux/libX11-devel to a version that resolves this vulnerability.
Fixed in 1.6.8-10.el8_10
Upgrade
Upgrade almalinux/libX11-xcb to a version that resolves this vulnerability.
Fixed in 1.6.8-10.el8_10

Event History

Oct 26, 2026

Advisory Published

via OSV·12:00 AM

Data Sourced

via OSV·12:00 AM

DescriptionAffected Software

Child vulnerabilities

Contains the following vulnerabilities.

CVE-2026-88806

Frequently Asked Questions

Who is exposed to this issue?

Systems with the affected AlmaLinux libX11 packages installed are potentially exposed when an application using libX11 connects to a malicious X server.

What does an attacker need to exploit the vulnerability?

The attacker needs to provide or control a malicious X server that a libX11-using client connects to. The available advisory data does not describe additional prerequisites or attack vectors.

How can I determine whether a system needs remediation?

Check whether the system has installed packages from the affected set: libX11, libX11-common, libX11-devel, or libX11-xcb. Compare installed package updates against the ALSA-2026:89730 security update.

ALSA-2026:89730: Important: libX11 security update

Affected Software

Remediation

Event History

Child vulnerabilities

Frequently Asked Questions

Who is exposed to this issue?

What does an attacker need to exploit the vulnerability?

How can I determine whether a system needs remediation?

Company

Resources

Contact

Frequently Asked Questions

Who is exposed to this issue?

What does an attacker need to exploit the vulnerability?

How can I determine whether a system needs remediation?