CVE-2026-64000 Linux CVE debrief

Who should care

Users of the Linux kernel, particularly those using the HSR protocol, should be aware of this vulnerability and take steps to ensure their systems are updated with the fix. This includes operators, platform administrators, vulnerability management teams, and security teams who may be impacted by the potential availability and integrity impacts of this vulnerability.

Technical summary

The vulnerability is caused by a potential out-of-bounds access in the supervision frame handling of the HSR protocol in the Linux kernel. This can occur when a truncated frame is received, and the entire TLV header is not linearized before access. The fix adds sizeof(struct hsr_sup_tlv) to the pskb_may_pull() calls to ensure the entire TLV header is linearized. Affected systems using the HSR protocol may experience availability and integrity impacts. Users of the Linux kernel, particularly those using the HSR protocol, should be aware of this vulnerability and take steps to ensure their systems are updated with the fix.

Defensive priority

Medium-High

Recommended defensive actions

• Update the Linux kernel to the latest version
• Ensure systems using the HSR protocol are patched
• Monitor for suspicious activity related to the HSR protocol
• 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
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-19T16:17:39.590Z and has not been modified since then. The NVD entry is currently Received. There is limited information available about the vulnerability, and defenders should verify the affected scope and severity with the vendor. The fix involves ensuring that the entire TLV header is linearized before access. The vulnerability is related to the handling of supervision frames in the HSR protocol in the Linux kernel. Defenders should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

Official resources