CVE-2026-46236: Linux Xbox Remote DMA Coherency Vulnerability

Technical summary

CVE-2026-46236 addresses a DMA coherency violation in the media/rc/xbox_remote driver within the Linux kernel. DMA-capable buffers must reside in memory regions that guarantee coherency between CPU caches and hardware access paths. By embedding the IO buffer within the device structure, the driver violates this architectural requirement. When the hardware performs DMA operations on this incorrectly-located buffer, cache coherency can be lost, leading to unpredictable behavior, memory corruption, or system hangs. The fix involves relocating the DMA buffer to properly-allocated, coherency-safe memory outside the device structure.

Business impact

For organizations running Linux systems with Xbox remote input devices, this vulnerability introduces a denial-of-service risk. An attacker with local access could trigger instability or crash affected systems by issuing commands through the remote. In server or embedded environments where Xbox remotes are used for management or automation, this could disrupt operations. The impact is localized to availability; no confidentiality or integrity compromise occurs. The practical risk depends on deployment scenarios—consumer desktops and edge devices with physical remotes are more exposed than data center infrastructure.

Affected systems

Linux systems running vulnerable kernel versions with the Xbox remote (xbox_remote) driver enabled. Affected systems include those with Xbox USB remote receivers connected or compiled with Xbox remote support. The vulnerability does not affect systems without this driver compiled or active, nor does it impact Windows or macOS systems. Determine exposure by checking kernel configuration for CONFIG_RC_XBOX and verifying kernel version against vendor patches.

Exploitability

Exploitation requires local system access and the ability to interact with the Xbox remote device or its input subsystem. An attacker cannot exploit this remotely over the network. Physical proximity to the device or a local user account is necessary. The attack complexity is low once local access is established—simply sending commands via the remote can trigger the DMA coherency issue. No special privileges are required beyond local user-level access, making it exploitable by unprivileged users. Practical exploitation depends on the specific hardware platform and kernel configuration.

Remediation

Apply a patched Linux kernel version that corrects the DMA buffer allocation in the xbox_remote driver. Verify against the official Linux kernel release notes and your distribution's security advisories for the specific fixed version. Interim mitigation: disable the Xbox remote driver if it is not actively used by compiling the kernel without CONFIG_RC_XBOX or blacklisting the module. Unplug Xbox remote receivers from affected systems until patched.

Patch guidance

Monitor your Linux distribution's security updates for kernel patches addressing CVE-2026-46236. Canonical, Red Hat, SUSE, and other vendors will release patched kernel versions through their standard update channels. Rebuild or reinstall the kernel with the fix applied. Test in a non-production environment first, particularly if running custom kernel configurations. For systems where the Xbox remote driver is not needed, the simplest remediation is kernel recompilation with the driver disabled. Verify the patch by confirming the DMA buffer allocation has been moved outside the device structure in the updated driver code.

Detection guidance

Monitor system logs for unusual kernel warnings, DMA-related errors, or sudden device driver failures associated with the Xbox remote module. On systems with verbose kernel logging enabled, look for coherency-related messages or repeated device timeouts. Memory corruption or unexpected system hangs coinciding with Xbox remote activity may indicate exploitation. Use kernel module inspection tools to verify the xbox_remote driver is properly loaded and check /proc/cmdline to confirm driver configuration. Intrusion detection systems should flag unusual local processes attempting to interact with rc/input subsystems.

Why prioritize this

This vulnerability merits medium priority for most organizations. While the CVSS score of 5.5 reflects local access requirements and availability-only impact, the practical risk varies by deployment. Organizations using Xbox remotes in critical systems or automation should prioritize patching. For typical enterprise environments without Xbox remote integration, this is a routine kernel update. Prioritize based on inventory of systems with the driver enabled and the sensitivity of those systems to availability disruptions.

Risk score, explained

The CVSS 3.1 score of 5.5 (Medium) reflects the following: Local Attack Vector (AV:L) because exploitation requires local system access; Low Attack Complexity (AC:L) as triggering the DMA issue does not require special conditions; Low Privileges Required (PR:L) since an unprivileged user can trigger it; No User Interaction (UI:N); Unchanged Scope (S:U); and High Availability Impact (A:H) because the DMA coherency violation can crash or hang the system. There is no Confidentiality or Integrity impact. The score appropriately captures a local denial-of-service condition that does not affect data security directly.

Frequently asked questions