CVE-2026-34195: GPU Sparse Memory Privilege Escalation

CVE-2026-34195 Overview

CVE-2026-34195 is an out-of-bounds write vulnerability [CWE-787] affecting GPU driver kernel components from Imagination Technologies. A non-privileged user can issue crafted GPU sparse memory API calls to trigger memory corruption in the kernel. The flaw originates from incorrect indexing of internal state during sparse allocation remapping operations.

Successful exploitation enables an attacker with low privileges to corrupt kernel memory, potentially leading to privilege escalation, arbitrary code execution in kernel context, or system compromise. The vulnerability impacts confidentiality, integrity, and availability of affected systems.

Critical Impact
A local non-privileged user can corrupt kernel memory through intentional GPU sparse memory API calls, leading to potential kernel-level code execution and full system compromise.

Affected Products

Imagination Technologies GPU drivers (specific versions not disclosed in NVD entry)
Systems integrating affected PowerVR/IMG GPU kernel drivers
Refer to the Imagination Technologies Security Advisory for the authoritative list of affected versions

Discovery Timeline

2026-06-12 - CVE-2026-34195 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2026-34195

Vulnerability Analysis

The vulnerability resides in the GPU driver code path that handles sparse memory allocation and remapping requests from userspace. Sparse memory APIs allow applications to allocate large virtual address ranges while backing only specific regions with physical memory. The driver maintains internal state structures that track which regions are mapped and the corresponding physical backing.

During sparse allocation remapping, the driver indexes into these internal state structures using values derived from user-controlled parameters. The indexing logic does not correctly validate or compute these offsets, allowing writes to occur beyond the bounds of the intended buffer. Because the writes happen in kernel context, an attacker can corrupt adjacent kernel data structures.

This class of bug commonly enables privilege escalation by overwriting function pointers, credential structures, or page table entries within the kernel.

Root Cause

The root cause is incorrect indexing of internal state when performing sparse allocation remapping. The driver computes an index for state lookup or update without sufficient bounds checking, resulting in an out-of-bounds write [CWE-787]. User-controlled inputs flow into the index calculation, making the condition reachable from a non-privileged process.

Attack Vector

An attacker requires local code execution as a non-privileged user on the target system. The attacker opens the GPU device interface exposed by the driver and issues a sequence of sparse memory API calls (allocation followed by remapping) with parameters crafted to produce an out-of-range index.

When the driver processes the remap request, it writes attacker-influenced data outside the intended buffer in kernel memory. Repeated invocations can be used to shape kernel memory layout (heap grooming) before triggering the final corrupting write, enabling reliable kernel-mode code execution or privilege escalation to root.

No verified public proof-of-concept code is available. Refer to the Imagination Technologies Security Advisory for vendor technical details.

Detection Methods for CVE-2026-34195

Indicators of Compromise

Unexpected kernel panics, oops messages, or GPU driver crashes referencing sparse allocation or memory mapping functions
Non-privileged processes opening GPU device nodes and issuing high volumes of sparse memory ioctl calls
Unexplained privilege escalation events where user processes transition to root without an authorized sudo or setuid path
Kernel log entries indicating memory corruption, slab corruption, or KASAN reports involving GPU driver symbols

Detection Strategies

Monitor kernel ring buffer (dmesg) for crashes or warnings emitted by the IMG/PowerVR driver during sparse mapping operations
Audit ioctl calls to GPU device files (/dev/dri/*, vendor-specific nodes) by non-privileged users and correlate with process lineage
Deploy kernel address sanitizer (KASAN) in test environments to surface out-of-bounds writes during driver fuzzing
Use EDR telemetry to flag processes opening GPU device interfaces and subsequently spawning privileged shells or modifying sensitive files

Monitoring Recommendations

Establish a baseline of legitimate GPU API usage per workload and alert on deviations from non-graphical processes
Forward kernel crash dumps and audit logs to a centralized SIEM for correlation across endpoints
Track installed GPU driver versions across the fleet and alert when systems run versions predating the vendor patch

How to Mitigate CVE-2026-34195

Immediate Actions Required

Apply the patched GPU driver release from Imagination Technologies or the downstream device vendor as soon as it is available
Inventory all systems running affected PowerVR/IMG GPU drivers, prioritizing multi-user systems and shared compute hosts
Restrict local access on affected systems and enforce the principle of least privilege for interactive accounts
Enable kernel exploit mitigations such as SMEP, SMAP, and KASLR where supported by the hardware and kernel

Patch Information

Consult the Imagination Technologies Security Advisory for the fixed driver versions and integration guidance. Because Imagination GPUs are licensed to multiple SoC and device manufacturers, downstream vendors (mobile OEMs, SBC suppliers, embedded platform providers) must ship the corrected driver in their respective firmware or kernel updates. Track advisories from your specific device vendor.

Workarounds

Limit access to GPU device nodes by tightening permissions on /dev/dri/* and vendor-specific device files to trusted groups only
Disable or unload the affected GPU kernel module on systems that do not require GPU acceleration
Apply mandatory access control policies (SELinux, AppArmor) to restrict which processes can issue ioctl calls to the GPU driver
Isolate untrusted workloads in virtual machines or containers with no direct GPU passthrough until patches are applied

bash

# Example: restrict GPU device access to a trusted group
sudo groupadd gpu-trusted
sudo chgrp gpu-trusted /dev/dri/renderD128
sudo chmod 660 /dev/dri/renderD128

# Example: unload the GPU driver module on headless systems
sudo lsmod | grep -i pvr
sudo modprobe -r pvrsrvkm

# Example: verify installed driver version
dmesg | grep -i "PowerVR\|pvr"