CVE-2026-46655virtio-win: Integer overflow causing a heap overflow in Viosock driver
- 7.8HighCVSS base score
- 0.18%Exploitation in 30 daysEPSS · top 93% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
Description
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
Timeline
ID reserved
By GitHub_M
- 4 months later
· 4 months later
Published
- 5 days later
· 5 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Awaiting Analysis | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.18% · top 93% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
virtio-win · kvm-guest-drivers-windows
- affected >= mm210, < mm320
References
References4
- https://github.com/virtio-win/kvm-guest-drivers-windows/security/advisories/GHSA-qrhp-4mhp-hjwh (opens in a new tab)x_refsource_CONFIRMexploit
- https://github.com/virtio-win/kvm-guest-drivers-windows/pull/1568 (opens in a new tab)x_refsource_MISC
- https://github.com/virtio-win/kvm-guest-drivers-windows/commit/c6bef93d7909584bbda4e5c87603ea175825f342 (opens in a new tab)x_refsource_MISC
- https://github.com/virtio-win/kvm-guest-drivers-windows/releases/tag/mm320 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-83179 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-46655)Record last updated .