Linux Kernel up to 7.2.5 ath12k ath12k_wmi_process_csa_switch_count_event num_vdevs out-of-bounds

Summaryinfo

A vulnerability categorized as very critical has been discovered in Linux Kernel up to 7.2.5. The affected element is the function ath12k_wmi_process_csa_switch_count_event of the component ath12k. Executing a manipulation of the argument num_vdevs can lead to out-of-bounds. This vulnerability appears as CVE-2026-90408. The attack requires local access. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as very critical was found in Linux Kernel up to 7.2.5. This vulnerability affects the function ath12k_wmi_process_csa_switch_count_event of the component ath12k. The manipulation of the argument num_vdevs with an unknown input leads to a out-of-bounds vulnerability. The CWE definition for the vulnerability is CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: wifi: ath12k: fix overreads in ath12k_wmi_process_csa_switch_count_event() There is no policy entry for WMI_TAG_PDEV_CSA_SWITCH_COUNT_STATUS_EVENT, so the parse infrastructure does not enforce a minimum length for the event struct. Additionally, the num_vdevs field is taken directly from firmware and used as a loop bound over the vdev_ids array without checking that it fits within the TLV payload. Either condition can cause an out-of-bounds read. Add a TLV policy entry for WMI_TAG_PDEV_CSA_SWITCH_COUNT_STATUS_EVENT so the parse infrastructure enforces a minimum length for the fixed-size event struct. Add a helper ath12k_wmi_tlv_data_len() to recover the payload length of a parsed TLV from the header preceding its data pointer. Use it in ath12k_wmi_process_csa_switch_count_event() to bound num_vdevs before the loop. Compile tested only.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-90408 since 09/11/2026. The exploitation appears to be easy. Local access is required to approach this attack. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 09/17/2026).

Upgrading to version 7.2.6 or 7.3-rc1 eliminates this vulnerability. Applying the patch bf97c9d5123859a07848462539153176db029f3a/878654eb78c6aa0ff585baf1376567c775ca28ec is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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