# CVE-2026-31770: hwmon: (occ) Fix division by zero in occ\_show\_power\_1()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-01 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.0

## Description

In the Linux kernel, the following vulnerability has been resolved: hwmon: (occ) Fix division by zero in occ_show_power_1() In occ_show_power_1() case 1, the accumulator is divided by update_tag without checking for zero. If no samples have been collected yet (e.g. during early boot when the sensor block is included but hasn't been updated), update_tag is zero, causing a kernel divide-by-zero crash. The 2019 fix in commit 211186cae14d ("hwmon: (occ) Fix division by zero issue") only addressed occ_get_powr_avg() used by occ_show_power_2() and occ_show_power_a0(). This separate code path in occ_show_power_1() was missed. Fix this by reusing the existing occ_get_powr_avg() helper, which already handles the zero-sample case and uses mul_u64_u32_div() to multiply before dividing for better precision. Move the helper above occ_show_power_1() so it is visible at the call site. [groeck: Fix alignment problems reported by checkpatch]

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
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## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c7d3712362c8ab8f82f441b649d9e446e7b9aa9d
- https://git.kernel.org/stable/c/53e6175756b8c474b6247bbcea0aad3d68357475
- https://git.kernel.org/stable/c/2502684b9e835de9a992ec47c3e6c6faabe3858d
- https://git.kernel.org/stable/c/37ae8fadc74ed68e5bc364ffd17746d88e449ae3
- https://git.kernel.org/stable/c/bbbefc48f6617cfb738dcff7f44beb50b5dfeb38
- https://git.kernel.org/stable/c/243d55bd3f08cb15eee9d63f4716d4d4cdd760f5
- https://git.kernel.org/stable/c/7b89ce0c98bf3015f493ca4285b2d1056cd8c733
- https://git.kernel.org/stable/c/39e2a5bf970402a8530a319cf06122e216ba57b8

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