CVE-2026-53203: Linux Kernel Buffer Overflow Vulnerability

CVE-2026-53203 Overview

CVE-2026-53203 is a buffer overflow vulnerability in the Linux kernel accel/ivpu driver, which supports Intel Versatile Processing Unit (VPU) accelerators. The flaw resides in the metric stream get_info_ioctl handler, where the kernel did not validate that the info size returned by the firmware fit within the allocated buffer. When the firmware returned a size larger than the buffer, the driver proceeded with an incorrect buffer copy. The fix rejects the operation with -EOVERFLOW when the returned size exceeds the buffer.

Critical Impact
A malicious or malfunctioning firmware response to the metric stream info query can trigger an out-of-bounds buffer copy in kernel space, potentially leading to kernel memory corruption or denial of service.

Affected Products

Linux kernel accel/ivpu driver (Intel VPU accelerator driver)
Stable kernel branches prior to commits 4e5047cc, d3c12ed3, fa598556, and fb176425
Systems with Intel VPU hardware exposing the ivpu ioctl interface to userspace

Discovery Timeline

2026-06-25 - CVE-2026-53203 published to NVD
2026-06-25 - Last updated in NVD database

Technical Details for CVE-2026-53203

Vulnerability Analysis

The vulnerability is in the accel/ivpu driver path handling the metric stream (MS) get_info ioctl. The driver allocates a buffer to hold metric stream info returned by the VPU firmware. The driver then issues a firmware query and receives back a size value describing how much data the firmware intends to copy into that buffer. Before the fix, the driver did not check that the firmware-reported size was less than or equal to the allocated buffer size. As a result, an oversized response caused a buffer copy to write beyond the allocated region, leading to a kernel heap buffer overflow [CWE-120].

The upstream patches add an explicit size comparison and return -EOVERFLOW to userspace when validation fails, aborting the copy.

Root Cause

The root cause is missing input validation on a length value returned by the VPU firmware. The driver trusted the firmware-supplied size without bounding it against the kernel-side allocation. Any code path that can influence or trigger an unexpected firmware response can therefore cause the kernel to copy more bytes than the buffer can hold.

Attack Vector

Exploitation requires a local user with access to the ivpu device node to issue the metric stream get_info ioctl. The unsafe copy occurs in kernel context, so successful exploitation could corrupt adjacent kernel memory. The most likely outcomes are kernel panic and denial of service. Memory corruption primitives in the kernel can, in some cases, be developed into privilege escalation, but this depends on heap layout and firmware behavior.

No verified public proof-of-concept is available. Technical details of the fix are documented in the kernel commits 4e5047cc, d3c12ed3, fa598556, and fb176425.

Detection Methods for CVE-2026-53203

Indicators of Compromise

Unexpected kernel oops or panic messages referencing ivpu or intel_vpu in dmesg and /var/log/kern.log
Slab corruption warnings or KASAN out-of-bounds write reports in kernel logs on systems with Intel VPU hardware
Repeated ioctl activity from unprivileged processes against /dev/accel/accel* device nodes

Detection Strategies

Audit kernel versions across the fleet and flag hosts running ivpu driver builds that predate the listed stable commits
Enable KASAN on test systems with Intel VPU hardware to surface out-of-bounds writes during fuzzing of the ivpu ioctl interface
Monitor process behavior for non-privileged binaries opening accelerator device nodes and issuing metric stream ioctls

Monitoring Recommendations

Forward kernel logs to a centralized log platform and alert on ivpu driver faults, slab corruption, and KASAN reports
Track ioctl syscalls targeting accelerator device files using auditd or eBPF-based tracing
Correlate kernel crash events with the process and user that issued the triggering ioctl

How to Mitigate CVE-2026-53203

Immediate Actions Required

Apply the stable kernel updates containing commits 4e5047cc, d3c12ed3, fa598556, or fb176425 from your distribution vendor
On systems that do not require Intel VPU acceleration, unload and blacklist the intel_vpu kernel module
Restrict access to /dev/accel/* device nodes to trusted users and services through file permissions and udev rules

Patch Information

The fix adds a size validation check in the metric stream get_info_ioctl handler. If the firmware-reported info size exceeds the allocated buffer, the driver returns -EOVERFLOW instead of performing the copy. The patches are tracked in the stable kernel commits referenced above and will be included in downstream distribution kernels as they pick up the stable updates.

Workarounds

Blacklist the intel_vpu module by adding blacklist intel_vpu to /etc/modprobe.d/ on hosts that do not need VPU functionality
Tighten permissions on accelerator device nodes so only required service accounts can issue ioctls
Limit untrusted local user access on systems with Intel VPU hardware until patched kernels are deployed

bash

# Configuration example: blacklist the ivpu driver until patched
echo 'blacklist intel_vpu' | sudo tee /etc/modprobe.d/blacklist-ivpu.conf
sudo rmmod intel_vpu 2>/dev/null || true
sudo update-initramfs -u