CVE-2026-90408 Linux CVE debrief

Who should care

Linux kernel maintainers, administrators, and security teams responsible for validating and patching Linux kernel deployments using ath12k should assess exposure and prioritize remediation. The vulnerability requires patching and input validation to prevent potential out-of-bounds read attempts. Affected operator, platform, vulnerability-management, and security-team impact should be evaluated to ensure effective remediation.

Why it matters

CVE-2026-90408 is a high-severity vulnerability in the Linux kernel's ath12k_wmi_process_csa_switch_count_event() function. It requires patching and input validation to prevent potential out-of-bounds read attempts. Linux kernel maintainers, administrators, and security teams should assess exposure and prioritize remediation.

• Potential for out-of-bounds read attempts
• Need for input validation and policy enforcement
• Patching priority for Linux kernel deployments

Technical summary

The ath12k_wmi_process_csa_switch_count_event() function in the Linux kernel is vulnerable to out-of-bounds reads due to missing policy entries and insufficient input validation. A fix has been implemented by adding a TLV policy entry and a helper function to validate the num_vdevs field, preventing potential out-of-bounds read attempts. Linux kernel maintainers, administrators, and security teams should assess exposure and prioritize remediation. The vulnerability has been resolved by adding a TLV policy entry for

Defensive priority

High-priority patching recommended for Linux kernel deployments using ath12k, with a focus on validating firmware inputs.

Recommended defensive actions

• Apply patches to Linux kernel deployments using ath12k
• Validate firmware inputs and enforce minimum length for event structs
• Monitor for potential out-of-bounds read attempts
• 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 and NVD entry provide details on the vulnerability in the Linux kernel's ath12k_wmi_process_csa_switch_count_event() function, which can cause an out-of-bounds read due to a missing policy entry for WMI_TAG_PDEV_CSA_SWITCH_COUNT_STATUS_EVENT and insufficient validation of the num_vdevs field. Testing and validation are required to confirm affected systems and remediation effectiveness. Linux kernel maintainers, administrators, and security teams should assess exposure and prioritize remediation. The fix involves adding

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.