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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-46655
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-18 17:16:57 UTC
Updated2026-09-30 17:31:44 UTC
Descriptionvirtio-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.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001800000 probability, percentile 0.069000000 (date 2026-10-02)

Problem Types: CWE-122 | CWE-190 | CWE-122 CWE-122: Heap-based Buffer Overflow | CWE-190 CWE-190: Integer Overflow or Wraparound

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Virtio-win Kvm-guest-drivers-windows affected >= mm210, < mm320 Not specified

References

ReferenceSourceLinkTags
github.com/virtio-win/kvm-guest-drivers-windows/commit/c6bef93d7909584bb... [email protected] github.com
github.com/virtio-win/kvm-guest-drivers-windows/releases/tag/mm320 [email protected] github.com
github.com/virtio-win/kvm-guest-drivers-windows/pull/1568 [email protected] github.com
github.com/virtio-win/kvm-guest-drivers-windows/security/advisories/GHSA... 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
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