Bug 2506818 (CVE-2026-64236)

Summary: CVE-2026-64236 kernel: i2c: davinci: fix division by zero on missing clock-frequency
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the i2c davinci driver of the Linux kernel. When the 'clock-frequency' property is missing from the device tree, the driver's fallback mechanism can lead to a division-by-zero error. This vulnerability can be triggered by a local attacker providing a malformed device tree, resulting in a kernel panic and a denial of service.
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Description OSIDB Bzimport 2026-07-24 16:05:43 UTC 
In the Linux kernel, the following vulnerability has been resolved:

i2c: davinci: fix division by zero on missing clock-frequency

When the 'clock-frequency' property is missing from the device tree,
the driver falls back to DAVINCI_I2C_DEFAULT_BUS_FREQ. However, this
macro was defined in kHz (100), whereas the device tree property is
expected in Hz.

The probe function divided the fallback value by 1000, causing
integer truncation that resulted in dev->bus_freq = 0. This triggered
a deterministic division-by-zero kernel panic when calculating clock
dividers later in the probe sequence.

Fix this by redefining DAVINCI_I2C_DEFAULT_BUS_FREQ in Hz (100000)
to match the expected device tree property unit, allowing the existing
division logic to work correctly for both cases.
Comment 1 Mauro Matteo Cascella 2026-07-28 12:09:23 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072440-CVE-2026-64236-b38d@gregkh/T