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PatchSiren cyber security CVE debrief

CVE-2026-64183 Linux CVE debrief

The Linux kernel has been updated to address a vulnerability where ACPI PRM calls could occur before the EFI runtime workqueue was allocated, leading to NULL pointer dereferences. This was resolved by splitting off the workqueue allocation into its own postcore initcall. The update ensures that EFI runtime calls, including PRM calls, are accessible to all code running at subsys_initcall() level. System administrators and security teams should review the update to ensure timely patching and mitigation.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-19
Original CVE updated
2026-07-19
Advisory published
2026-07-19
Advisory updated
2026-07-19

Who should care

System administrators and security teams responsible for Linux kernel-based systems should be aware of this update to ensure timely patching and mitigation. They should review system configurations to prevent exploitation and monitor system logs for potential NULL pointer dereference errors.

Technical summary

The vulnerability was caused by ACPI PRM calls being delegated to a workqueue running in a kernel thread before the EFI runtime workqueue was allocated. This led to NULL pointer dereferences. The fix involves allocating the runtime workqueue before ACPI init, ensuring that EFI runtime calls are accessible to all code running at subsys_initcall() level. The update does not introduce any new functionality but rather rearranges the initialization process to prevent the vulnerability.

Defensive priority

Medium

Recommended defensive actions

  • Review and apply the kernel update to ensure the EFI runtime workqueue is allocated before ACPI init.
  • Verify system configurations to prevent exploitation.
  • Monitor system logs for potential NULL pointer dereference errors.
  • Perform a thorough review of system configurations and kernel versions to identify potential vulnerabilities.
  • Implement compensating controls for exposed systems while remediation is scheduled and verified.
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented.
  • Review relevant monitoring, detection, and logs for exposed assets that need extra review.

Evidence notes

The CVE record was published on 2026-07-19T16:18:00.703Z and has not been modified since then. The NVD entry is currently Received. There is no additional information available about the vulnerability beyond what is provided in the official CVE record and NVD detail page.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-19T16:18:00.703Z and has not been modified since then.