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...

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...

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...

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: 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...

RHEL 7 : tigervnc (RHSA-2026:46473)

The remote Redhat Enterprise Linux 7 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:46473 advisory. Virtual Network Computing VNC is a remote display system which allows users to view a computing desktop environment not only on the machine...

MiracleLinux 9 : xorg-x11-server-Xwayland-24.1.9-4.el9_8.2 (AXSA:2026-1355:07)

The remote MiracleLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2026-1355:07 advisory. xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libXfont2 name length mismatch...

RHEL 9 : tigervnc (RHSA-2026:46392)

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:46392 advisory. Virtual Network Computing VNC is a remote display system which allows users to view a computing desktop environment not only on the machine...

RHEL 8 : tigervnc (RHSA-2026:46382)

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:46382 advisory. Virtual Network Computing VNC is a remote display system which allows users to view a computing desktop environment not only on the machine...

RHEL 9 : tigervnc (RHSA-2026:46456)

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:46456 advisory. Virtual Network Computing VNC is a remote display system which allows users to view a computing desktop environment not only on the machine...

MiracleLinux 9 : xorg-x11-server-1.20.11-34.el9_8.2 (AXSA:2026-1354:12)

The remote MiracleLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2026-1354:12 advisory. xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libXfont2 name length mismatch...

RHEL 9 : tigervnc (RHSA-2026:46377)

The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:46377 advisory. Virtual Network Computing VNC is a remote display system which allows users to view a computing desktop environment not only on the machine...

RHEL 8 : tigervnc (RHSA-2026:46460)

The remote Redhat Enterprise Linux 8 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:46460 advisory. Virtual Network Computing VNC is a remote display system which allows users to view a computing desktop environment not only on the machine...

Alibaba Cloud Linux 3 : 0211: xorg-x11-server-Xwayland (ALINUX3-SA-2026:0211)

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALINUX3-SA-2026:0211 advisory. Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities: CVE-2026-55999: Local attackers with a X...

Alibaba Cloud Linux 3 : 0213: xorg-x11-server (ALINUX3-SA-2026:0213)

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by a vulnerability as referenced in the ALINUX3-SA-2026:0213 advisory. Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities: CVE-2026-55999: Local attackers with a X connection...

Oracle Linux 10 : xorg-x11-server-Xwayland (ELSA-2026-19125)

The remote Oracle Linux 10 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2026-19125 advisory. - CVE fix for: CVE-2026-50256, CVE-2026-50257, CVE-2026-50258, CVE-2026-50259, CVE-2026-50260, CVE-2026-50261, CVE-2026-50262, CVE-2026-50263 Resolve...

Amazon Linux 2023 : xorg-x11-server-Xwayland, xorg-x11-server-Xwayland-devel (ALAS2023-2026-1944)

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1944 advisory. glamor Font Atlas Heap Buffer Overflow CVE-2026-55999 GLX contextTags Use-After-Free in CommonMakeCurrent CVE-2026-56000 Tenable has extracted the preceding description block directly from the...