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: 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 information disclosure in CreateSaverWindow()

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...

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

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...

xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB SetMap request via mapWidths indexing

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. XkbSetMapChecks declares a fixed-size stack buffer mapWidths256 indexed by key type index. The helper function CheckKeyTypes writes to this buffer at a client-controlled offset, allowing a stack buffer overflow. This...

xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB key types due to unchecked shift levels

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. The X server has multiple stack buffers sized XkbMaxShiftLevel XkbNumKbdGroups but CheckKeyTypes does not verify or clamp non-canonical key types to XkbMaxShiftLevel. A client can change key types to excessive shift...

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

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...

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...

Important: Red Hat Security Advisory: tigervnc security update

An update for tigervnc is now available for Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System CVSS base score, which gives a detailed severity rating, is...

OESA-2026-3026 xorg-x11-server security update

X.Org X11 X server Security Fixes: Local attackers with a X connection able to provide PCX fonts to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a heap buffer overflow via SetFont due to missing glyph boundary checks.CVE-2026-55999...

xorg-x11-server-Xwayland security update

An update is available for xorg-x11-server-Xwayland. This update affects Rocky Linux 10. 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-2026:38489 Important: xorg-x11-server-Xwayland security update

Xwayland is an X server for running X clients under Wayland. Security Fixes: xorg: X11: xserver: X.org: glamor Font Atlas Heap Buffer Overflow CVE-2026-55999 X.org: xorg-x11-server: GLX contextTags Use-After-Free in CommonMakeCurrent CVE-2026-56000 For more details about the security issues,...

xorg-x11-server-Xwayland security 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-2026:38490 Important: xorg-x11-server-Xwayland security update

Xwayland is an X server for running X clients under Wayland. Security Fixes: xorg: X11: xserver: X.org: glamor Font Atlas Heap Buffer Overflow CVE-2026-55999 X.org: xorg-x11-server: GLX contextTags Use-After-Free in CommonMakeCurrent CVE-2026-56000 For more details about the security issues,...

RHSA-2026:38810 Red Hat Security Advisory: xorg-x11-server-Xwayland security update

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RHSA-2026:38490 Red Hat Security Advisory: xorg-x11-server-Xwayland security update

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xorg-x11-server-Xwayland security update

An update is available for xorg-x11-server-Xwayland. This update affects Rocky Linux 8. 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-2026:38488 Important: xorg-x11-server-Xwayland security update

Xwayland is an X server for running X clients under Wayland. Security Fixes: xorg: X11: xserver: X.org: glamor Font Atlas Heap Buffer Overflow CVE-2026-55999 For more details about the security issues, including the impact, a CVSS score, acknowledgments, and other related information, refer to th...

RockyLinux 8 : xorg-x11-server-Xwayland (RLSA-2026:38488)

The remote RockyLinux 8 host has packages installed that are affected by a vulnerability as referenced in the RLSA-2026:38488 advisory. xorg: X11: xserver: X.org: glamor Font Atlas Heap Buffer Overflow CVE-2026-55999 Tenable has extracted the preceding description block directly from the RockyLin...

openSUSE 16 Security Update : xwayland (openSUSE-SU-2026:21283-1)

The remote openSUSE 16 host has packages installed that are affected by multiple vulnerabilities as referenced in the openSUSE-SU-2026:21283-1 advisory. This update for xwayland fixes the following issues - CVE-2026-55999: missing bounds check in glamorfontget can lead to a heap buffer overflow...