{"id":"CVE-2026-46655","aliases":[],"url":"https://o3.security/vulnerability/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…","details":"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.","published":"2026-09-18T17:16:57.373","modified":"2026-09-18T17:16:57.373","cvss":{"score":7.8,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":{"url":"https://github.com/virtio-win/kvm-guest-drivers-windows/commit/c6bef93d7909584bbda4e5c87603ea175825f342","label":"virtio-win/kvm-guest-drivers-windows@c6bef93"},"references":[{"type":"WEB","url":"https://github.com/virtio-win/kvm-guest-drivers-windows/commit/c6bef93d7909584bbda4e5c87603ea175825f342"},{"type":"WEB","url":"https://github.com/virtio-win/kvm-guest-drivers-windows/pull/1568"},{"type":"WEB","url":"https://github.com/virtio-win/kvm-guest-drivers-windows/releases/tag/mm320"},{"type":"WEB","url":"https://github.com/virtio-win/kvm-guest-drivers-windows/security/advisories/GHSA-qrhp-4mhp-hjwh"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-09-18T17:16:57.373"}}