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 and Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On. Red Hat Product Security has rated this update as having a security impact of Important. A Common...

CVE-2026-56003 libXfont2 computeProps Property Buffer Heap Buffer Overflow

A heap buffer overflow due to missing size checking in the property buffer when parsing PCF files in libXfont2 ComputeScaledProperties before libXfont2 before 2.0.8 could be used by attackers using authenticated X clients to execute code within the X server...

CVE-2026-56000 xorg-x11-server / xwayland GLX contextTags Use-After-Free in CommonMakeCurrent()

Local attackers with a X connection able to provide GLX commit to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a Heap Use After Free, due to CommonMakeCurrent pointing into potentially reallocated memory...

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...

xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds read/write in GLX ChangeDrawableAttributes

An out-of-bounds read flaw was found in the X.Org X server and Xwayland in glXDispChangeDrawableAttributes. A wrong size validation check can read a client-controlled number of bytes, exceeding the request buffer, leading to information disclosure. A write path also exists but requires byte-swapp...

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...

EUVD-2026-38413

A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack ca...

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...

xorg-x11-server-Xwayland security, bug fix, and enhancement update

An update is available for xorg-x11-server-Xwayland. This update affects Rocky Linux 9. A Common Vulnerability Scoring System CVSS base score, which gives a detailed severity rating, is available for each vulnerability from the CVE list Xwayland is an X server for running X clients under Wayland...

RLSA-2026:26709 Important: xorg-x11-server security, bug fix, and enhancement 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-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias resolution du...

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...

Important: xorg-x11-server security, bug fix, and enhancement 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-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias resolution du...

The vulnerability of the _XkbSetMapChecks() function in the Wayland protocol implementation for X.Org XWaylan, as well as in the X.Org Server implementation of the X Window System, allows a malicious actor to gain elevated privileges and cause service failures.

The vulnerability of the XkbSetMapChecks function in the Wayland protocol implementation for X.Org XWaylan, as well as in the X.Org Server implementation of the X Window System, is related to the execution of operations outside of the buffer in memory. Exploiting this vulnerability can allow...

[SECURITY] Fedora 43 Update: xorg-x11-server-21.1.23-1.fc43

X.Org X11 X server...

Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in xkb key types due to unchecked shift levels

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Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in syncchangecounter()

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SUSE 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...

EUVD-2026-34817

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...

CVE-2026-50261 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...

CVE-2026-50261

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...