CVE-2026-98408

What it actually does

clk_get_rate() returning zero leads to an unchecked division operation in the rzv2h watchdog driver, triggering a kernel panic via improper input validation.

Why it matters to the business

Unexpected system crashes or reboots on affected Linux systems can interrupt services and require manual recovery, though prevalence remains low given the specific hardware dependency.

How an attack unfolds

An attacker or misconfigured environment causes clk_get_rate() to return zero during watchdog probe or initialization; the driver performs a division without checking the result, resulting in an immediate kernel panic.

How to fix it

Apply the upstream kernel patch that adds a zero check before the division in the rzv2h watchdog driver; rebuild and deploy the updated kernel image.

How to confirm the fix worked

Confirm the presence of the zero-rate guard in the rzv2h watchdog source; boot test systems and verify no panic occurs when clk_get_rate() returns zero.

Typical attack path

1. Obtain ability to influence clock configuration or trigger driver load on rzv2h hardware
2. Invoke clk_get_rate() path returning zero
3. Watchdog initialization code executes division without guard
4. Kernel panic occurs, crashing the system

How to detect it

Search kernel panic logs and dmesg output for divide error messages occurring during rzv2h watchdog initialization or probe.

• divide error: 0000
• rzv2h_wdt_probe
• watchdog: rzv2h

What your security team should do

• Prioritize patching systems running the rzv2h watchdog driver within standard maintenance windows
• Monitor kernel logs for divide-by-zero panics referencing the watchdog module
• Review hardware clock configurations to reduce likelihood of zero-rate returns