CVE-2026-53118 describes a use-after-free (UAF) vulnerability in the Linux kernel's vdpa driver. The root cause is that when a driver is probed via __driver_attach(), the bus' match() callback is invoked without holding the device lock, which leads to accessing the driver_override field without proper synchronization. This unsafe access can cause a UAF condition. The fix involves using the driver-core driver_override infrastructure that manages locking internally, preventing the unsafe access. The vulnerability affects multiple Linux kernel versions prior to 7.0.0-28.28 and related builds. The issue has been patched and is documented in Ubuntu security advisories USN-8566-1 and USN-8568-1.

The vulnerability allows local attackers with limited privileges to exploit a use-after-free condition in the vdpa driver, potentially leading to privilege escalation and full system compromise. The CVSS v3.1 score is 7.8, indicating a high impact on confidentiality, integrity, and availability. No known exploits are reported in the wild at this time.

A patch is available and should be applied by updating to Linux kernel versions 7.0.0-28.28 or later, or the corresponding fixed versions listed in the Ubuntu advisories USN-8566-1 and USN-8568-1. After updating, a system reboot is required. Due to an ABI change, third-party kernel modules must be recompiled and reinstalled. Follow vendor instructions for applying updates and recompiling modules. No additional mitigation actions are required beyond applying the official fix.