CVE-2026-5164
MediumCVSS 6.7Exploitation Probability (EPSS)
Low risk1th percentile - higher than 1% of all known CVEs
Summary
In virtio-win, the RhelDoUnMap() function does not properly validate the number of descriptors provided by a user during an unmap request. A local user could supply an excessive number of descriptors, leading to a buffer overrun and a system crash (Denial of Service).
Risk Assessment
May cause a buffer overrun and system crash by a local user, resulting in denial of service. Affects virtualized environments using virtio-win drivers.
Recommendation
Update virtio-win drivers to a version containing the descriptor count validation fix in RhelDoUnMap(). Restrict local access to virtual machines with affected drivers.
Other vulnerabilities in virtio-win
See all- CVE-2026-46655High
In virtio-win 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. This is fixed in mm320.
- CVE-2026-5165Medium
In virtio-win, the VirtIO Block (BLK) device fails to properly manage memory during a device reset, resulting in a use-after-free vulnerability. A local attacker could corrupt system memory, potentially causing instability or unexpected behavior.
Original NVD description (English source)
A flaw was found in virtio-win. The `RhelDoUnMap()` function does not properly validate the number of descriptors provided by a user during an unmap request. A local user could exploit this input validation vulnerability by supplying an excessive number of descriptors, leading to a buffer overrun. This can cause a system crash, resulting in a Denial of Service (DoS).
Vulnerability data from NVD (NIST) · CISA KEV · EPSS