23 Oct 2026 15:48:27 UTC
virtio-win: Integer overflow causing a heap overflow in Viosock driver
cve-program · CVE-2026-46655 · Published
CVE-2026-46655
virtio-win: Integer overflow causing a heap overflow in Viosock driver
CVSS 3.1 7.8 HIGHCheck source for fixed versionsKEV status unknown
cve-program · CVE-2026-46655
Publishedvirtio-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.
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