Linux Kernel EUVD-2026-66455

The target system must be running a vulnerable Linux kernel version with the amdgpu driver loaded and bound to AMD GPU hardware that exposes UVD (Unified Video Decoder) functionality - not all AMD GPU generations include UVD. The attacker requires a local shell with at minimum standard unprivileged credentials (PR:L per CVSS). The exploit is triggered through the UVD decode interface, so the /dev/dri device nodes must be accessible to the attacker's user account (the default on many desktop Linux distributions). Systems without AMD GPU hardware, those where amdgpu is not loaded, systems where GPU device node access is restricted to a privileged group, and VMs without GPU passthrough are not exploitable. No network exposure is involved and no user interaction from a privileged user is required.

The CVSS 7.8 score with vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H accurately captures the threat model: this is a local privilege escalation requiring only a shell account on a system with an AMD GPU. Attack complexity is low once local access is obtained, as the overflow condition is deterministically triggerable via the UVD interface. The S:U scope is consistent with a within-kernel exploit that does not directly break out to affect other virtual machines or hosts. No EPSS score was provided and no CISA KEV listing exists, so the real-world exploitation rate is unconfirmed - the risk signals available suggest a vulnerability that is serious but not yet observed in active campaigns. The hardware prerequisite (AMD GPU required) meaningfully limits the population of exploitable hosts; servers and cloud instances without GPU passthrough or dedicated AMD GPU hardware are unaffected. Priority should be proportional to whether affected systems are multi-user or host untrusted workloads - kernel memory corruption flaws, even with a local attack vector, warrant prompt patching on shared infrastructure.

A low-privileged user on a Linux system with an AMD GPU opens a UVD decode session and submits a crafted image descriptor specifying a pitch value above 4096. The kernel's minimum size validation overflows, accepting a buffer far smaller than required. The kernel then writes decoded image data past the end of the allocated buffer, corrupting adjacent kernel heap memory. The attacker leverages this memory corruption to overwrite kernel function pointers or credential structures, escalating to root. No public exploit code has been identified at time of analysis.