CVE-2026-45875 Overview
CVE-2026-45875 is a resource leak vulnerability in the Linux kernel's mfd/arizona driver, which supports Wolfson/Cirrus Logic Arizona-class audio codecs. The flaw resides in the WM5102 codec initialization path, where an error returned by wm5102_clear_write_sequencer() causes the function to return directly without releasing previously enabled regulators. The bypassed cleanup leaves voltage regulators powered on, producing a kernel resource leak on the affected device.
Critical Impact
Failed initialization of WM5102 audio codecs leaves hardware regulators enabled, leading to power resource leaks and potential device instability on systems using Arizona-class MFD drivers.
Affected Products
- Linux kernel mfd/arizona subsystem (WM5102 codec support)
- Multiple stable Linux kernel branches (patches issued across several trees)
- Systems integrating Cirrus Logic/Wolfson Arizona-class audio codecs
Discovery Timeline
- 2026-05-27 - CVE-2026-45875 published to NVD
- 2026-05-27 - Last updated in NVD database
Technical Details for CVE-2026-45875
Vulnerability Analysis
The vulnerability exists in the WM5102 initialization sequence within the Linux kernel mfd/arizona driver. During codec setup, the driver enables a set of voltage regulators required to communicate with the hardware. It then invokes wm5102_clear_write_sequencer() to clear the codec's internal write sequencer state.
When wm5102_clear_write_sequencer() returns an error, the original code path performs a direct return to the caller. This bypasses the err_reset label and the regulator cleanup logic that follows. The regulators remain enabled, leaving hardware components powered indefinitely until the next driver reload or system reboot.
The fix replaces the direct return with a goto err_reset, ensuring the established cleanup sequence releases the regulators before propagating the error. This pattern is a classic kernel resource management bug where early-exit paths skip required teardown.
Root Cause
The root cause is incorrect error-handling flow in the WM5102 probe/initialization function. A premature return statement on a failure branch skips the goto err_reset cleanup label that other failure branches use, breaking the symmetric acquire/release pattern expected for kernel resources.
Attack Vector
The issue is not remotely exploitable. It triggers only when wm5102_clear_write_sequencer() fails on a system with the affected codec hardware. Practical impact is limited to local availability and power-management correctness on devices that ship Arizona-class audio codecs. No memory-safety corruption or privilege escalation is documented.
The vulnerability is described in prose only. No verified proof-of-concept code is available; refer to the upstream patches for the precise diff. See the Linux Kernel Patch 2049820 and Linux Kernel Patch 933c546 for the canonical fix.
Detection Methods for CVE-2026-45875
Indicators of Compromise
- Kernel log entries from the arizona or wm5102 driver reporting failures from wm5102_clear_write_sequencer() during probe.
- Regulator framework debug output (/sys/kernel/debug/regulator/regulator_summary) showing Arizona-related regulators enabled with no active consumers after a failed codec probe.
- Unexpected power draw or thermal readings on embedded devices using WM5102 codecs after audio driver initialization errors.
Detection Strategies
- Inventory Linux systems running kernels predating the upstream fix commits referenced in the NVD entry and flag those that load mfd-arizona or wm5102 modules.
- Parse dmesg and persistent kernel logs for repeated probe failures in the Arizona MFD subsystem.
- Monitor regulator state via sysfs/debugfs on suspect platforms and compare against expected idle state after driver unload.
Monitoring Recommendations
- Forward kernel logs to a central logging or SIEM platform and alert on Arizona/WM5102 probe errors.
- Track kernel versions across the Linux fleet to identify hosts missing the stable backports listed in the NVD references.
- For embedded or industrial deployments, baseline power consumption after boot and alert on persistent deviations following driver load events.
How to Mitigate CVE-2026-45875
Immediate Actions Required
- Identify systems and embedded products running affected Linux kernel versions that include the mfd/arizona WM5102 support.
- Apply the stable kernel updates that incorporate the upstream fix referenced in the NVD entry.
- Reboot affected devices after patching to ensure the corrected initialization path is in effect.
Patch Information
The issue is resolved by replacing the direct return in the WM5102 initialization path with a goto err_reset, allowing the existing cleanup logic to disable the previously enabled regulators. The fix has been backported across multiple stable branches. See the upstream commits: 2049820, 3ea0169, 445cec7, 4feb753, 54eafc1, 5a49237, 933c546, and e0527c0.
Workarounds
- If patching is not immediately possible, avoid loading the mfd-arizona/wm5102 modules on systems where the codec is not required.
- On embedded devices that depend on the codec, schedule maintenance windows to reload the driver and reset regulator state if a probe failure is observed.
- Track kernel module load and unload events to identify devices repeatedly hitting the failure path until the patch is deployed.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
