CVE-2026-50258 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...

CVE-2026-50259 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...

CVE-2026-50259 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...

CVE-2026-50258 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...

CVE-2026-50258 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...

CVE-2026-50259 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...

EUVD-2026-34815

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...

EUVD-2026-34814

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...

CVE-2026-50259

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...

CVE-2026-50257

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...

CVE-2026-50258

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...

CVE-2026-50256

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...

CVE-2026-50256 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...

CVE-2026-50256

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...

CVE-2026-50257 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...

CVE-2026-50256 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...

CVE-2026-50257 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...

EUVD-2026-34813

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...

EUVD-2026-34812

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...

CVE-2026-50257

CVE-2026-50257 affects the X.Org X server and Xwayland, with a use-after-free in miSyncDestroyFence(). A client that sets multiple fence triggers can trigger a use-after-free function pointer call when a second X connection destroys the fence. This could crash the X server or allow privilege esca...