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CVE-2026-46655

virtio-win: Integer overflow causing a heap overflow in Viosock driver PUBLISHED

Description (CNA)

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 (CNA)

Vendor / productVersions
virtio-win / kvm-guest-drivers-windowsaffected >= mm210, < mm320

CWE

CWE-122, CWE-190

References

ADP enrichment

CISA-ADP

No English description supplied.