CVE-2026-31770 Linux CVE debrief

Who should care

Linux kernel maintainers, distro security teams, embedded/device vendors shipping affected kernel versions, and operators who rely on hwmon/occ sensor reporting for platform monitoring. Systems that may expose the occ sensor block during early boot should pay attention, because the fault can appear before normal sampling has occurred.

Technical summary

The vulnerable code path is in occ_show_power_1(). In case 1, it divides an accumulator by update_tag without checking whether any samples exist. If update_tag is zero, the kernel can hit a divide-by-zero fault and crash. The fix reuses the existing occ_get_powr_avg() helper, which already handles the zero-sample case and uses mul_u64_u32_div() for better precision. NVD maps this to CWE-369 and a CVSS 3.1 vector of AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Defensive priority

Medium. This is a local, availability-only kernel crash with no direct confidentiality or integrity impact in the supplied data, but kernel panics are operationally important and can affect uptime on systems using the affected driver path.

Recommended defensive actions

• Update Linux kernel packages to a version that includes the upstream/stable fix referenced by the official kernel patches.
• Confirm whether your deployed kernels fall within the affected version ranges listed by NVD, especially the supported stable lines ending before the fixed releases.
• If you vendor-backport kernels, verify that the occ driver fix was included in your downstream tree and not only in upstream stable branches.
• Prioritize patching systems that may initialize or expose the OCC hwmon sensor block during boot or on systems where a kernel crash would cause service interruption.
• Use the official CVE and NVD records plus the linked kernel patches to validate remediation status in your environment.

Evidence notes

The CVE description states that occ_show_power_1() case 1 divided by update_tag without checking for zero, and that the earlier 2019 fix only covered occ_get_powr_avg() used by other show paths. NVD lists CWE-369 and a CVSS 3.1 vector of AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. NVD also provides affected-version criteria for multiple Linux kernel release lines and includes official kernel patch references on git.kernel.org.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.