CVE-2026-64213: hwmon: (lm90) Add lock protection to lm90_alert
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (lm90) Add lock protection to lm90alert
Sashiko reports:
lm90alert() executes in the smbus alert context and calls lm90updateconfreg() to disable the hardware alert line, without acquiring hwmonlock.
Concurrently, sysfs write operations (such as lm90writeconvrate) hold the hwmonlock, temporarily modify data->config, and then restore it.
If an alert interrupt occurs concurrently with a sysfs write, the sysfs path will overwrite the alert handler's modifications to data->config and the hardware register.
This unintentionally re-enables the hardware alert line while the alarm is still active, causing an interrupt storm.
Add the missing lock to lm90alert() to solve the problem.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Configuration
Modify lm90_alert() to acquire hwmon_lock before calling lm90_update_confreg() (which disables the hardware alert line), temporarily modify data->config while the lock is held, and then restore the original data->config before releasing hwmon_lock to prevent sysfs write operations from overwriting alert-handler modifications and causing an interrupt storm.
Linux kernel hwmon (lm90) lm90_alert() locking = Add lock protection using hwmon_lock around temporary updates to data->config (disable hardware alert line via lm90_update_confreg(), then restore data->config)
Event History
Frequently Asked Questions
What is the severity of CVE-2026-64213?
The severity of CVE-2026-64213 is medium with a score of 5.5 according to CVSS 3.1.
How do I fix CVE-2026-64213?
To fix CVE-2026-64213, you need to update to the patched version of the Linux kernel where the vulnerability has been addressed.
What systems are affected by CVE-2026-64213?
CVE-2026-64213 affects systems running the vulnerable versions of the Linux kernel that include the hwmon lm90 driver.
What type of vulnerability is CVE-2026-64213?
CVE-2026-64213 is a locking issue in the hwmon subsystem of the Linux kernel, specifically related to concurrent access.
What are the potential consequences of CVE-2026-64213?
The potential consequence of CVE-2026-64213 includes denial of service (DoS) due to improper handling of hardware alerts.