CVE-2026-80676

A flaw was found in the Linux kernel's Hyper-V (hv) VMBus driver. When a driver is being initialized, a specific callback function attempts to access a memory region (driver_override) without proper synchronization. This oversight can lead to a Use-After-Free (UAF) vulnerability, where a local attacker could potentially exploit this to cause a system crash (denial of service) or execute unauthorized code.

Moderate-severity use-after-free vulnerability in the Linux kernel's Hyper-V VMBus driver, affecting the kernel and kernel-rt components of Red Hat Enterprise Linux 7 through 10 and Red Hat In-Vehicle OS 2. When a driver is probed through __driver_attach(), the VMBus bus match() callback is intentionally invoked without the device lock held and dereferences the driver_override field without synchronization; if another thread concurrently replaces or removes the driver_override string through sysfs, the memory can be freed while vmbus_match() is still using it. A local attacker with privileges on an affected system could race these operations to cause a kernel crash (denial of service) or, in the worst case, execute unauthorized code, although the Red Hat CVSS score (5.5, CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) reflects availability impact only. The fix for the affected update streams is currently deferred because exploitation requires local privileged access and a successful race window, which limits the practical risk; residual risk remains for systems where untrusted local users have the privileges needed to manipulate driver_override and trigger repeated device driver probing. The RHEL 6 Extended Lifecycle Support stream is out of support scope for this issue.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.