CVE-2026-46655

Summary

virtio-win provides Windows paravirtualized drivers for QEMU and KVM. From mm210 until mm320, the Viosock driver permits a low-privilege local process to submit an IOCTL_SELECT request with attacker-controlled VIRTIO_VSOCK_SELECT.Fdss[*].fd_count values that overflow the 32-bit sum used by VIOSockSelect for bounds checking. The wrapped sum can pass the FD_SETSIZE check even though an individual descriptor count is much larger than the expected limit. VIOSockSelectCopyFds then iterates using the unchecked count and writes beyond the allocated pPkt->Fds array in the NonPagedPool kernel heap. Successful exploitation can corrupt kernel memory and enable privilege escalation in a Windows guest running the driver. This issue is fixed in mm320.

Affected Software

VendorProductVersion RangeStatus
virtio-winkvm-guest-drivers-windows>= mm210, < mm320affected

Weaknesses

  • CWE-122: CWE-122: Heap-based Buffer Overflow
  • CWE-190: CWE-190: Integer Overflow or Wraparound

References