xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in SyncChangeCounter()

A use-after-free flaw was found in the X.Org X server and Xwayland in SyncChangeCounter. A client that sets up multiple SyncCounters can trigger a use-after-free when destroying those counters via a second client connection while changing those counters. This may be used to crash the server, or f...

TencentOS Server 4: tigervnc (TSSA-2026:0412)

The version of Tencent Linux installed on the remote TencentOS Server 4 host is prior to tested version. It is, therefore, affected by a vulnerability as referenced in the TSSA-2026:0412 advisory. Package updates are available for TencentOS Server 4 that fix the following vulnerabilities:...

SUSE CVE-2026-50257

A use-after-free flaw was found in the X.Org X server and Xwayland in miSyncDestroyFence. A client that sets up multiple fence triggers can trigger a use-after-free function pointer call. An attacker would connect to the X server to set up a fence and await that fence, then a second X connection...

CVE-2026-50263

A use-after-free flaw was found in the X.Org X server and Xwayland in CreateSaverWindow. A client can trigger a use-after-free read after changing window attributes and forcing the screen saver, leading to information disclosure...

CVE-2026-50264 Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: out-of-bounds heap write in dri2 drigetbuffers/drigetbufferswithformat

An out-of-bounds write flaw was found in the X.Org X server and Xwayland in DRIGetBuffers/DRIGetBuffersWithFormat. A client that requests multiple DRI2BufferBackLeft attachments and one DRI2BufferFrontLeft can trigger an out-of-bounds heap write. This may be used to crash the server, or for...

CVE-2026-50260

A use-after-free flaw was found in the X.Org X server and Xwayland in FreeCounter. A client that sets up multiple SyncCounters and awaits on those triggers can trigger a use-after-free when destroying those counters via a second client connection. This may be used to crash the server, or for...

CVE-2026-50256 Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libxfont2 name length mismatch

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. A mismatch between the X server and the libXfont2 library's maximum font name length can cause a stack buffer overflow during font alias resolution. The server allocates a 256 byte stack buffer but libXfont2's alias...

CVE-2026-50257

CVE-2026-50257 affects the X.Org X server and Xwayland, with a use-after-free in miSyncDestroyFence(). A client that sets multiple fence triggers can trigger a use-after-free function pointer call when a second X connection destroys the fence. This could crash the X server or allow privilege esca...

xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory corruption

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...

xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory access

A flaw was found in the X.Org X server's XKB key types request validation. A local attacker could send a specially crafted request to the X server, leading to an out-of-bounds memory access vulnerability. This could result in the disclosure of sensitive information or cause the server to crash,...

xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map handling

A flaw was found in the X.Org X server. This integer underflow vulnerability, specifically in the XKB compatibility map handling, allows an attacker with local or remote X11 server access to trigger a buffer read overrun. This can lead to memory-safety violations and potentially a denial of servi...

Important: Red Hat Security Advisory: xorg-x11-server security update

An update for xorg-x11-server is now available for Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support, Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions, and Red Hat Enterprise Linux 8.6 Telecommunications Update Service. Red Hat Product Security has rated this...

xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory corruption

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...

xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory corruption

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...

ALSA-2026:19343 Important: xorg-x11-server security update

X.Org is an open-source implementation of the X Window System. It provides the basic low-level functionality that full-fledged graphical user interfaces are designed upon. Security Fixes: xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map handling...

RLSA-2026:13414 Important: tigervnc security update

Virtual Network Computing VNC is a remote display system which allows users to view a computing desktop environment not only on the machine where it is running, but from anywhere on the Internet and from a wide variety of machine architectures. TigerVNC is a suite of VNC servers and clients...

CVE-2026-34000

A flaw was found in the X.Org X server. This out-of-bounds read vulnerability in the XKB geometry processing, specifically within the CheckSetGeom and XkbAddGeomKeyAlias functions, allows an attacker to read uninitialized or out-of-bounds memory. An attacker with a connection to the X11 server,...

Fedora 44 : xorg-x11-server (2026-cf9e55a7a0)

The remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-cf9e55a7a0 advisory. Update to xserver 21.1.22, CVE fix for: CVE-2026-33999, CVE-2026-34000, CVE-2026-34001, CVE-2026-34002, CVE-2026-34003 Tenable has extracted the...

CVE-2026-34003 Xorg: xwayland: x.org x server: information exposure and denial of service via out-of-bounds memory access

A flaw was found in the X.Org X server's XKB key types request validation. A local attacker could send a specially crafted request to the X server, leading to an out-of-bounds memory access vulnerability. This could result in the disclosure of sensitive information or cause the server to crash,...

RLSA-2025:20961 Moderate: xorg-x11-server security update

X.Org is an open-source implementation of the X Window System. It provides the basic low-level functionality that full-fledged graphical user interfaces are designed upon. Security Fixes: xorg: xmayland: Use-after-free in XPresentNotify structure creation CVE-2025-62229 xorg: xwayland:...