{"id":"CVE-2026-46655","title":"virtio-win provides Windows paravirtualized drivers for QEMU and KVM","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 with attacker-controlled VIRTIO_VSOCK_SELECT.Fdss[*]…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-122","CWE-190"],"vendor":"virtio-win","product":"kvm-guest-drivers-windows","affected":["kvm-guest-drivers-windows >= mm210, < mm320"],"published":"2026-09-18","updated":"2026-09-30","sourceUpdated":"2026-09-30T17:31:44.573","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-46655","references":[{"url":"https://github.com/virtio-win/kvm-guest-drivers-windows/commit/c6bef93d7909584bbda4e5c87603ea175825f342","label":"security-advisories@github.com"},{"url":"https://github.com/virtio-win/kvm-guest-drivers-windows/pull/1568","label":"security-advisories@github.com"},{"url":"https://github.com/virtio-win/kvm-guest-drivers-windows/releases/tag/mm320","label":"security-advisories@github.com"},{"url":"https://github.com/virtio-win/kvm-guest-drivers-windows/security/advisories/GHSA-qrhp-4mhp-hjwh","label":"security-advisories@github.com"},{"url":"https://github.com/virtio-win/kvm-guest-drivers-windows/security/advisories/GHSA-qrhp-4mhp-hjwh","label":"134c704f-9b21-4f2e-91b3-4a467353bcc0"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46655.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-46655"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2489170"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-46655"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-46655"}],"tags":["nvd","cve.org","exploit-available","csaf","vex","red-hat"],"epss":0.00175,"epssPercentile":0.06966,"exploitAvailable":true,"ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"total","timestamp":"2026-09-23T19:14:57.635548Z"},"ingestedAt":"2026-09-18T17:46:41.519Z","slug":"CVE-2026-46655","body":"## Overview\n\nvirtio-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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-09-22 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-46655.json)","depth":"midnight","depthScore":55,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":12,"ransomware":0},"changes":[{"seq":209849,"id":"CVE-2026-46655","ts":1790191922724,"field":"exploit_available","old":"false","new":"true"}]}