Bug 2516405 (CVE-2026-72394)

Summary: CVE-2026-72394 kernel: hwmon: (aspeed-g6-pwm-tach) Guard fan RPM calculation against divide-by-zero
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's aspeed-g6-pwm-tach driver. This vulnerability arises when the system attempts to calculate fan rotations per minute (RPM) using a tachometer value of zero, which can occur due to hardware glitches or specific conditions. Without proper validation, this zero value is used in a division, causing a critical error known as a kernel panic. This can lead to a system crash, effectively denying service to legitimate users.
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Description OSIDB Bzimport 2026-08-15 06:10:44 UTC 
In the Linux kernel, the following vulnerability has been resolved:

hwmon: (aspeed-g6-pwm-tach) Guard fan RPM calculation against divide-by-zero

Sashiko reports:

In the aspeed-g6-pwm-tacho driver, the aspeed_tach_val_to_rpm() function
calculates the fan RPM using the tachometer value. However, it does not
check if the tachometer value is zero before performing the division.

If the hardware reports a tachometer value of 0 (which can happen due to
an extremely fast pulse, a stuck edge, or a hardware glitch), the
calculated tach_div evaluates to 0. The subsequent call to do_div() with
tach_div as the divisor triggers a divide-by-zero exception, leading to
a kernel panic.

Check the divisor against zero to fix the problem.
Comment 1 Keith Grant 2026-08-19 15:15:08 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081520-CVE-2026-72394-c44c@gregkh/T