published September 4, 2026
In the Linux kernel, the following vulnerability has been resolved:
HID: hyperv: validate initial device info bounds
The Hyper-V synthetic HID host supplies SYNTH_HID_INITIAL_DEVICE_INFO
messages that contain a HID descriptor followed by the report descriptor
bytes. mousevsc_on_receive_device_info() trusts bLength and
wDescriptorLength without checking that the received packet contains both
byte ranges.
A malformed host or backend message can therefore make the guest read
past the received VMBus packet while copying the report descriptor. Pass
the received initial-device-info size into the parser and reject
descriptor lengths that exceed the packet.
Impact: A malicious Hyper-V host or backend can crash a guest by sending
a short initial device-info message with an oversized HID report
descriptor length.