Detections
Analytics

AlmaLinux 8 : xorg-x11-server-Xwayland (ALSA-2026:26562)

medium Nessus Plugin ID 321499

Synopsis

The remote AlmaLinux host is missing one or more security updates.

Description

The remote AlmaLinux 8 host has a package installed that is affected by multiple vulnerabilities as referenced in the ALSA-2026:26562 advisory.

 * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libXfont2 name length mismatch (CVE-2026-50256)
 * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in miSyncDestroyFence() (CVE-2026-50257)
 * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB key types due to unchecked shift levels (CVE-2026-50258)
 * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB SetMap request via mapWidths indexing (CVE-2026-50259)
 * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in FreeCounter() (CVE-2026-50260)
 * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in SyncChangeCounter() (CVE-2026-50261)
 * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds read/write in GLX ChangeDrawableAttributes (CVE-2026-50262)
 * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free information disclosure in CreateSaverWindow() (CVE-2026-50263)
 * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds heap write in DRI2 DRIGetBuffers/DRIGetBuffersWithFormat (CVE-2026-50264)


 Bug Fix(es) and Enhancement(s):

 * [xwayland] Backport other security fixes without a CVE assigned [almalinux-8.10.z] (JIRA:AlmaLinux-184293)

Tenable has extracted the preceding description block directly from the AlmaLinux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected xorg-x11-server-Xwayland package.

See Also

https://errata.almalinux.org/8/ALSA-2026-26562.html

https://access.redhat.com/errata/RHSA-2026:26562

Plugin Details

Severity: Medium

ID: 321499

File Name: alma_linux_ALSA-2026-26562.nasl

Version: 1.1

Type: Local

Published: 6/18/2026

Updated: 6/18/2026

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

Vector: CVSS2#AV:L/AC:L/Au:S/C:C/I:C/A:C

CVSS Score Source: CVE-2026-50264

CVSS v3

Risk Factor: Medium

Base Score: 5.5

Temporal Score: 4.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS Score Source: CVE-2026-50263

Vulnerability Information

CPE: cpe:/o:alma:linux:8, p-cpe:/a:alma:linux:xorg-x11-server-xwayland, cpe:/o:alma:linux:8::powertools, cpe:/o:alma:linux:8::baseos, cpe:/o:alma:linux:8::appstream, cpe:/o:alma:linux:8::nfv, cpe:/o:alma:linux:8::realtime, cpe:/o:alma:linux:8::highavailability, cpe:/o:alma:linux:8::resilientstorage, cpe:/o:alma:linux:8::sap, cpe:/o:alma:linux:8::sap_hana, cpe:/o:alma:linux:8::supplementary

Required KB Items: Host/local_checks_enabled, Host/cpu, Host/AlmaLinux/release, Host/AlmaLinux/rpm-list

Exploit Ease: No known exploits are available

Patch Publication Date: 6/17/2026

Vulnerability Publication Date: 6/1/2026

Reference Information

CVE: CVE-2026-50256, CVE-2026-50257, CVE-2026-50258, CVE-2026-50259, CVE-2026-50260, CVE-2026-50261, CVE-2026-50262, CVE-2026-50263, CVE-2026-50264

CWE: 121, 125, 416, 787

RHSA: 2026:26562