# CVE-2026-98409: Linux kernel RTD119x watchdog division by zero

Source: https://junglewise.ai/threats/cve-2026-98409-in-the-linux-kernel-the-following-vulnerability-has-been-resolved  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-14. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-98409 · Severity: info · Published 2026-10-14

The Linux kernel's RTD119x watchdog driver can crash with a division by zero panic during device initialization if the clock rate cannot be determined. This causes a system denial of service on Realtek RTD1295-based devices, preventing the watchdog from functioning.

Technologies: [Linux kernel](https://junglewise.ai/threats/technologies/x-linux-kernel).

## Quick answers

**Is CVE-2026-98409 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-98409 being exploited in the wild.

**How severe is CVE-2026-98409?** Informational severity, published 14 October 2026.

**Which products and versions are affected?** Linux kernel all versions with rtd119x watchdog driver (from kernel 2bdf6acbfead onwards).

**Is there a fix for CVE-2026-98409?** A patch was published on 2026-09-16. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-98409 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-98409?** Check whether you run Linux kernel at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The rtd119x_wdt driver calls clk_get_rate() to obtain a clock frequency, then immediately divides by this value without checking whether it returned zero. A zero clock rate can occur in certain hardware configurations or clock tree states, triggering a kernel panic. The fix adds a validation check that returns -EINVAL if the clock rate is 0, preventing the division.

## Affected products

- Linux kernel all versions with rtd119x watchdog driver (from kernel 2bdf6acbfead onwards)

## Timeline

- 2026-09-13: disclosed
- 2026-09-16: patched
- 2026-10-14: advisory

## References

- [https://git.kernel.org/stable/c/1f22001b34984350844d629862f70934770cb796](https://git.kernel.org/stable/c/1f22001b34984350844d629862f70934770cb796)
- [https://git.kernel.org/stable/c/5af7d2cbd20f893def03c8310a460ade66a5d822](https://git.kernel.org/stable/c/5af7d2cbd20f893def03c8310a460ade66a5d822)

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