SB20260528268 - Red Hat Enterprise Linux 8 update for xorg-x11-server-Xwayland
Published: May 28, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 5 vulnerabilities.
1) Integer underflow (CVE-ID: CVE-2026-33999)
CWE-ID: CWE-191 - Integer underflow
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a local user to disclose sensitive information.
The vulnerability exists due to an integer underflow in XkbSetCompatMap() when processing a future request after a previously truncated compat buffer left unused space. A local user can gain access to sensitive information.
2) Out-of-bounds read (CVE-ID: CVE-2026-34000)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a local user to disclose sensitive information.
The vulnerability exists due to an out-of-bounds read in CheckSetGeom() when handling key alias entries and validating only the first key name. A local user can gain access to sensitive information.
3) Use-after-free (CVE-ID: CVE-2026-34001)
CWE-ID: CWE-416 - Use After Free
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a use-after-free in miSyncTriggerFence() when walking the list of fences to trigger. A local user can trigger fence processing to cause a denial of service.
The issue occurs because freeing the await resource removes subsequent trigger entries from the list during iteration.
4) Out-of-bounds read (CVE-ID: CVE-2026-34002)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a local user to disclose sensitive information.
The vulnerability exists due to an out-of-bounds read in CheckModifierMap() when parsing client request data without verifying that reads remain within request bounds. A local user disclose sensitive information.
5) Out-of-bounds read (CVE-ID: CVE-2026-34003)
CWE-ID: CWE-125 - Out-of-bounds read
CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
The vulnerability allows a local user to disclose sensitive information.
The vulnerability exists due to an out-of-bounds read in CheckKeyTypes() when processing a client request without ensuring that reads remain within request bounds. A local user can gain access to sensitive information.
Remediation
Install update from vendor's website.