CVE-2026-55999

CVE-2026-55999 affects xorg-server (before 21.2.24) and xwayland (before 24.1.13). A local attacker with a X connection can trigger a heap buffer overflow in glamor font atlas via SetFont due to missing glyph boundary checks. Impact is a potential heap corruption, with high likelihood of exploita...

CVE-2026-55999 xorg-server / xwayland glamor font atlas Heap Buffer Overflow

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-server / xwayland glamor font atlas Heap Buffer Overflow

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-server / xwayland glamor font atlas Heap Buffer Overflow

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...

Security update for xorg-x11-server

This update for xorg-x11-server fixes the following issue CVE-2026-55999: missing bounds check in glamorfontget can lead to a heap buffer overflow when a font loaded from a malicious PCF file is processed bsc1268893. Patch Instructions: To install this SUSE update use the SUSE recommended...

CVE-2026-56000

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...

CVE-2026-56000

CVE-2026-56000 affects the X.org X server stack: specifically xorg-x11-server and xwayland. A Use-After-Free in CommonMakeCurrent() exposes heap corruption when GLX commit data is processed over an X connection, due to a pointer into memory that may be reallocated. Impact is described as local/pr...

EUVD-2026-42202

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...

Security update for xorg-x11-server

This update for xorg-x11-server fixes the following issues CVE-2026-55999: missing bounds check in glamorfontget can lead to a heap buffer overflow when a font loaded from a malicious PCF file is processed bsc1268893. CVE-2026-56000: improper memory management in CommonMakeCurrent can lead to a...

SUSE-SU-2026:2788-1 Security update for xorg-x11-server

This update for xorg-x11-server fixes the following issues - CVE-2026-55999: missing bounds check in glamorfontget can lead to a heap buffer overflow when a font loaded from a malicious PCF file is processed bsc1268893. - CVE-2026-56000: improper memory management in CommonMakeCurrent can lead to...

Amazon Linux 2 : tigervnc, --advisory ALAS2-2026-3792 (ALAS-2026-3792)

The version of tigervnc installed on the remote host is prior to 1.8.0-24. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-3792 advisory. A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. XkbSetMapChecks declares a fixed-size stack buff...

Linux Distros Unpatched Vulnerability : CVE-2026-55999

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - 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...

PT-2026-56335

Name of the Vulnerable Software and Affected Versions xorg-server versions prior to 21.2.24 xwayland versions prior to 24.1.13 Description Local attackers with an X connection can cause a Heap Use After Free, a condition where the system continues to use a memory address after it has been freed,...

RHSA-2026:36086 Red Hat Security Advisory: xorg-x11-server security update

Bulletin has no description...

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: 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: 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: 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: 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...

MiracleLinux 9 : xorg-x11-server-1.20.11-34.el9_8 (AXSA:2026-1212:08)

The remote MiracleLinux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the AXSA:2026-1212:08 advisory. xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map handling CVE-2026-33999 xorg: xwayland: X.Org X...