CVE-2026-31570 Linux CVE debrief

Who should care

Linux system administrators and security teams should assess exposure and apply patches to prevent out-of-bounds heap access in CAN gateway functionality. They should also inventory Linux systems using CAN gateway functionality, monitor Linux kernel updates for CAN gateway fixes, and apply them as necessary. Additionally, they should review compensating controls for exposed systems while remediation is scheduled and verified, and check relevant monitoring,

Why it matters

CVE-2026-31570 is a high-severity vulnerability in the Linux kernel's CAN gateway implementation that can lead to out-of-bounds heap access. Linux system administrators and security teams should assess exposure, apply patches, and monitor kernel updates to prevent potential heap memory corruption or information disclosure.

• Potential for heap memory corruption or information disclosure
• Requires verification of affected versions and patch application
• Necessitates monitoring Linux kernel updates for CAN gateway fixes

Technical summary

The `cgw_csum_crc8_rel()` function in the Linux kernel's CAN gateway implementation did not properly validate indices, allowing for a potential read and write of heap memory outside the bounds of a CAN frame. This issue has been resolved in various Linux kernel commits, including e7c99348b0612b2bc02d5ce6ff9873261cc7605f and 999ca48d55a8a46da21519db7e834e5867200379. The vulnerability was caused by the function's incorrect usage of raw s8 fields instead of computed variables, and its resolution involved updating the function to match the companion `cgw_csum_xor_rel()` function

Defensive priority

High

Recommended defensive actions

• Review and apply Linux kernel patches for CAN gateway to prevent out-of-bounds heap access
• Inventory Linux systems using CAN gateway functionality to assess exposure
• Monitor Linux kernel updates for CAN gateway fixes and apply as necessary
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and source item provide details on the vulnerability, including a description of the issue and affected versions. However, the corpus does not establish specific exploitation or impact details, requiring verification from official sources.

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.