CVE-2026-23422: Linux Kernel dpaa2-switch DoS Vulnerability

CVE-2026-23422 Overview

A vulnerability has been identified in the Linux kernel's dpaa2-switch driver that can result in an interrupt storm condition. The issue exists in the IRQ handler where an out-of-bounds if_id value detection fails to properly clear the interrupt status, leading to continuous interrupt generation that can severely impact system performance and availability.

The vulnerability was introduced as a side effect of commit 31a7a0bbeb00 which added bounds checking for if_id in the IRQ handler to prevent out-of-bounds memory access. While the bounds check was correctly implemented, the code path that handles invalid if_id values failed to clear the interrupt status register, creating a condition where the interrupt continuously fires.

Critical Impact

Systems utilizing the dpaa2-switch network driver may experience denial of service conditions through interrupt storms that can render the system unresponsive or cause significant performance degradation.

Affected Products

• Linux kernel versions with dpaa2-switch driver (DPAA2 network switching functionality)
• NXP QorIQ Layerscape platforms using DPAA2 network infrastructure
• Embedded systems and network appliances utilizing affected kernel versions

Discovery Timeline

• 2026-04-03 - CVE CVE-2026-23422 published to NVD
• 2026-04-03 - Last updated in NVD database

Technical Details for CVE-2026-23422

Vulnerability Analysis

This vulnerability represents a denial of service condition stemming from improper interrupt handling in the Linux kernel's dpaa2-switch driver. The dpaa2-switch component is part of the Data Path Acceleration Architecture (DPAA2) used in NXP QorIQ network processors for high-performance packet switching.

The flaw exists in the interrupt request (IRQ) handler logic. When the handler receives an interrupt with an if_id value that falls outside the valid range, the existing bounds check correctly identifies the invalid condition and prevents out-of-bounds memory access. However, the error handling path fails to acknowledge and clear the interrupt status before returning. Since the interrupt remains asserted, the hardware immediately re-triggers the interrupt handler upon return, creating an interrupt storm.

An interrupt storm is a condition where the CPU becomes overwhelmed processing the same interrupt repeatedly, consuming all available processing cycles and effectively starving other system processes. This can lead to complete system unresponsiveness, dropped network packets, and in severe cases may require a hard reset to recover.

Root Cause

The root cause is an incomplete error handling path in the dpaa2-switch IRQ handler. When commit 31a7a0bbeb00 introduced bounds checking for if_id, the developers correctly added validation to prevent out-of-bounds array access. However, the early return path for invalid if_id values bypasses the interrupt acknowledgment code that normally clears the interrupt status register.

In proper interrupt handling, the handler must always acknowledge the interrupt to the hardware before returning, regardless of whether the data associated with the interrupt is valid. The fix ensures that the interrupt status is cleared even when an out-of-bounds if_id is detected, preventing the continuous re-triggering of the interrupt handler.

Attack Vector

The attack vector for this vulnerability depends on how the invalid if_id value can be introduced. Potential scenarios include:

The vulnerability can be triggered when the hardware or firmware provides an unexpected if_id value to the driver. This could occur due to hardware malfunction, firmware bugs, or in scenarios where an attacker has the ability to manipulate the hardware state or inject malformed data into the switch fabric.

In environments where the DPAA2 switch is exposed to untrusted network traffic or where an attacker has local access to the system, careful manipulation of network conditions or direct hardware interaction could potentially trigger the condition. The result is a denial of service affecting the entire system, not just the network functionality.

Detection Methods for CVE-2026-23422

Indicators of Compromise

• Abnormally high CPU utilization with the majority of time spent in interrupt handling (soft IRQ processing)
• System log messages indicating dpaa2-switch IRQ handler errors or bounds check failures
• Network interface unresponsiveness on DPAA2-based switching ports
• System performance degradation or complete unresponsiveness requiring hard reset

Detection Strategies

• Monitor /proc/interrupts for rapidly incrementing interrupt counts on dpaa2-switch related IRQ lines
• Configure kernel tracing on the dpaa2-switch driver to detect out-of-bounds if_id conditions
• Implement system monitoring alerts for CPU utilization spikes correlated with interrupt processing
• Review kernel logs using dmesg for any dpaa2-switch driver warnings or errors

Monitoring Recommendations

• Deploy system monitoring agents that track interrupt rates and CPU utilization patterns
• Configure SentinelOne Singularity platform to monitor for kernel driver anomalies and unexpected system behavior
• Establish baseline metrics for normal interrupt handling to enable anomaly detection
• Implement automated alerting for sustained high interrupt rates that may indicate an active exploit

How to Mitigate CVE-2026-23422

Immediate Actions Required

• Apply the latest kernel patches that address the interrupt status clearing in the dpaa2-switch driver
• For systems that cannot be immediately patched, consider disabling the dpaa2-switch driver if the functionality is not critical
• Monitor affected systems closely for signs of interrupt storms or performance degradation
• Prepare recovery procedures including the ability to perform hard resets if systems become unresponsive

Patch Information

The Linux kernel maintainers have released patches across multiple stable kernel branches to address this vulnerability. The fix ensures that the interrupt status is properly cleared after detecting an out-of-bounds if_id, preventing the interrupt storm condition.

Patches are available through the following kernel git commits:

• Patch commit 00f42ace446f
• Patch commit 28fd8ac1d493
• Patch commit 74badb9c20b1
• Patch commit b5bababe7703
• Patch commit c7becfe3e604
• Patch commit fa4412cdc517

Update to a kernel version containing one of these patches based on your distribution and kernel branch.

Workarounds

• If patching is not immediately possible, blacklist the dpaa2-switch module on systems where DPAA2 switching functionality is not required
• Implement hardware watchdog timers to automatically recover from system hangs caused by interrupt storms
• Configure boot parameters to limit interrupt affinity and isolate potential impact to specific CPU cores
• Consider deploying redundant systems to maintain availability while affected systems are patched

# Configuration example
# To blacklist the dpaa2-switch driver if not needed:
echo "blacklist dpaa2-switch" | sudo tee /etc/modprobe.d/blacklist-dpaa2-switch.conf

# To verify the module is not loaded:
lsmod | grep dpaa2

# To remove the module if currently loaded (requires no active use):
sudo modprobe -r dpaa2-switch