CVE-2026-46655virtio-win: Integer overflow causing a heap overflow in Viosock driver
Updated under an hour ago ()
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It affects virtio-win kvm-guest-drivers-windows. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-122, CWE-190
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 23, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
virtio-win kvm-guest-drivers-windows virtio_win:kvm_guest_drivers_windows (from the name) | from mm210, < mm320 | CNA record |
References
- https://github.com/virtio-win/kvm-guest-drivers-windows/security/advisories/GHSA-qrhp-4mhp-hjwhx-refsource-confirm
- https://github.com/virtio-win/kvm-guest-drivers-windows/pull/1568x-refsource-misc
- https://github.com/virtio-win/kvm-guest-drivers-windows/commit/c6bef93d7909584bbda4e5c87603ea175825f342x-refsource-misc
- https://github.com/virtio-win/kvm-guest-drivers-windows/releases/tag/mm320x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.