Bug 2506799 (CVE-2026-64213)

Summary: CVE-2026-64213 kernel: hwmon: (lm90) Add lock protection to lm90_alert
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2026-07-24 16:03:52 UTC 
In the Linux kernel, the following vulnerability has been resolved:

hwmon: (lm90) Add lock protection to lm90_alert

Sashiko reports:

lm90_alert() executes in the smbus alert context and calls
lm90_update_confreg() to disable the hardware alert line, without
acquiring hwmon_lock.

Concurrently, sysfs write operations (such as lm90_write_convrate) hold
the hwmon_lock, 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 lm90_alert() to solve the problem.
Comment 1 Mauro Matteo Cascella 2026-07-28 10:17:38 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072414-CVE-2026-64213-dfb0@gregkh/T