CVE-2026-56001

A heap buffer overflow in BitmapScaleBitmaps in libXfont2 before 2.0.8 due to an overflowing 32bit size could be used by attackers able to access the X Server to execute code within the X server cont...

EUVD-2026-42210

A heap buffer overflow in BitmapScaleBitmaps in libXfont2 before 2.0.8 due to an overflowing 32bit size could be used by attackers able to access the X Server to execute code within the X server cont...

CVE-2026-56001 libXfont2 BitmapScaleBitmaps Integer Overflow Heap Buffer Overflow

A heap buffer overflow in BitmapScaleBitmaps in libXfont2 before 2.0.8 due to an overflowing 32bit size could be used by attackers able to access the X Server to execute code within the X server cont...

CVE-2026-55999

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

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...

PT-2026-56334

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 buffer overflow by providing PCX fonts to the X server. This occurs due to missing glyph boundary checks...

PT-2026-56391

Name of the Vulnerable Software and Affected Versions libXfont2 versions prior to 2.0.8 Description A heap buffer overflow occurs when parsing PCF files due to missing size checking in the property buffer within the ComputeScaledProperties function. Authenticated X clients can exploit this issue ...

PT-2026-56383

Name of the Vulnerable Software and Affected Versions libXfont2 versions prior to 2.0.8 Description A heap-based buffer overflow exists in the BitmapScaleBitmaps function. The issue is caused by an integer overflow where a 32-bit size calculation wraps, resulting in an undersized heap allocation...

Linux Distros Unpatched Vulnerability : CVE-2026-56002

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - A heap bufferflow in pcfReadFont due to missing glyph bounds checking in libXfont2 before 2.0.8 allows attackers authenticated as X client to execute code withi...

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: 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 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: 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...

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...

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 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...

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: 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...