Skip to main content

X.Org Server CVE-2026-34001

| EUVDEUVD-2026-25230 HIGH
Expired Pointer Dereference (CWE-825)
2026-04-23 redhat GHSA-cjgm-66pw-5r9r
7.8
CVSS 3.1 · Vendor: redhat
Share

Severity by source

Vendor (redhat) PRIMARY
7.8 HIGH
AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vuln.today AI
7.8 HIGH

A low-privileged local client can reach the XSYNC path with low complexity and no interaction; use-after-free in the privileged server yields high C/I/A within an unchanged scope.

3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
SUSE
HIGH
qualitative
Red Hat
7.8 HIGH
qualitative

Primary rating from Vendor (redhat).

CVSS VectorVendor: redhat

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

4
Analysis Generated
Jul 24, 2026 - 04:45 vuln.today
Patch released
Apr 28, 2026 - 20:30 nvd
Patch available
EUVD ID Assigned
Apr 23, 2026 - 16:00 euvd
EUVD-2026-25230
CVE Published
Apr 23, 2026 - 14:54 nvd
HIGH 7.8

DescriptionCVE.org

A flaw was found in the X.Org X server. This use-after-free vulnerability occurs in the XSYNC fence triggering logic, specifically within the miSyncTriggerFence() function. An attacker with access to the X11 server can exploit this without user interaction, leading to a server crash and potentially enabling memory corruption. This could result in a denial of service or further compromise of the system.

AnalysisAI

Local privilege-relevant memory corruption in the X.Org X server arises from a use-after-free in the XSYNC fence-triggering path (miSyncTriggerFence()), letting any client with a connection to the display crash the server or corrupt heap memory without user interaction. Rated CVSS 7.8 with total technical impact per CISA SSVC, it currently shows no public exploit identified at time of analysis, no CISA KEV listing, and a very low EPSS of 0.01% (3rd percentile). Because the X server frequently runs with elevated privileges, successful memory corruption could escalate beyond denial of service.

Technical ContextAI

The X.Org X server is the reference implementation of the X11 display server that mediates between graphical clients and input/output hardware on Linux and Unix desktops. The XSYNC extension provides synchronization primitives (counters and fences) that clients use to coordinate rendering; the miSyncTriggerFence() routine in the machine-independent (mi) sync layer fires callbacks when a fence is triggered. The defect is classified CWE-825 (Expired Pointer Dereference), a use-after-free variant: the fence trigger logic dereferences a pointer to an object that has already been freed, so attacker-influenced heap contents can be interpreted as valid server structures, producing a crash or controllable memory corruption within the server process.

RemediationAI

Patch available per vendor advisory: apply the updated xorg-x11-server packages from your distribution. Red Hat users should install the fixes delivered in RHSA-2026:10739, RHSA-2026:11352, and RHSA-2026:11369 (https://access.redhat.com/errata/RHSA-2026:10739); SUSE users should apply the corresponding SUSE-SU-2026:1328 through 1335 or SUSE-SU-2026:21211 updates (https://www.suse.com/support/update/SUSE-SU-2026:1328/), then restart the display server or reboot so the running server picks up the fix. As a compensating control until patching, restrict who can connect to the X server: disable X11 TCP listening (run with '-nolisten tcp', the modern default) and avoid enabling remote X forwarding for untrusted users to shrink the set of clients that can reach the vulnerable XSYNC path; on shared hosts, limit local interactive/SSH access to trusted accounts. These controls reduce exposure but do not eliminate risk for legitimate local users, and disabling X forwarding may break remote GUI workflows that rely on it.

CVE-2026-18663 MEDIUM
5.9 Aug 12

Heap corruption via double-free in 389-ds-base's LDAP control parsing allows an unauthenticated remote attacker to crash

CVE-2026-4631 CRITICAL POC
9.8 Apr 07

Remote code execution in Cockpit's web interface allows unauthenticated attackers to execute arbitrary commands on the h

CVE-2026-4480 CRITICAL POC
9.0 May 26

Remote code execution in Samba's printing subsystem allows remote attackers to inject arbitrary shell commands via craft

CVE-2026-18922 CRITICAL
9.8 Sep 07

Authentication bypass in 389 Directory Server (shipped as Red Hat Directory Server 11-13 and within RHEL 6-10) lets remo

CVE-2026-14544 CRITICAL
9.8 Jul 03

Remote code execution and privilege escalation in HPLIP (HP Linux Imaging and Printing) affects the hpcups print filter

CVE-2026-76578 CRITICAL
9.8 Sep 07

Unauthenticated privilege escalation in FreeIPA (Red Hat Identity Management) allows a remote attacker to gain genuine a

CVE-2026-5121 HIGH
7.5 Mar 30

Remote code execution in libarchive on 32-bit systems allows unauthenticated attackers to execute arbitrary code via spe

CVE-2026-28369 CRITICAL
9.1 Mar 27

HTTP request smuggling in Undertow (the embedded web server underpinning JBoss EAP, Red Hat Data Grid, and Apache Camel

CVE-2026-28368 CRITICAL
9.1 Mar 27

HTTP request smuggling in Red Hat Undertow allows remote unauthenticated attackers to bypass front-end security controls

CVE-2026-33845 CRITICAL
9.1 Apr 30

Out-of-bounds read in the GnuTLS DTLS handshake reassembly logic lets remote unauthenticated attackers trigger an intege

CVE-2026-28367 CRITICAL
9.1 Mar 27

HTTP request smuggling in Undertow allows remote unauthenticated attackers to send `\r\r\r` as a header block terminator

CVE-2026-16526 HIGH
8.8 Jul 30

Local privilege escalation in Performance Co-Pilot (PCP) on Red Hat Enterprise Linux 6 through 10 and OpenShift Containe

Vendor StatusVendor

SUSE

Severity: High
Product Status
Image SLES15-SP4-SAP Image SLES15-SP4-SAP-Azure Image SLES15-SP4-SAP-EC2 Image SLES15-SP4-SAP-GCE Image SLES15-SP4-SAPCAL Image SLES15-SP4-SAPCAL-Azure Image SLES15-SP4-SAPCAL-EC2 Image SLES15-SP4-SAPCAL-GCE Affected
Image SLES15-SP5-SAPCAL-Azure Image SLES15-SP5-SAPCAL-GCE Affected
Image SLES15-SP6-SAP Image SLES15-SP6-SAP-EC2 Image SLES15-SP6-SAPCAL Image SLES15-SP6-SAPCAL-EC2 Affected
SUSE Liberty Linux 9 Fixed
SUSE Linux Enterprise Desktop 15 SP7 SUSE Linux Enterprise Server 15 SP7 SUSE Linux Enterprise Server for SAP Applications 15 SP7 Fixed

Share

CVE-2026-34001 vulnerability details – vuln.today

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy