UBUNTU-CVE-2026-90407: Medium severity ubuntu/linux-hwe-edge vulnerability
In the Linux kernel, the following vulnerability has been resolved: wifi: ath11k: fix overreads in ath11kwmiprocesscsaswitchcountevent() There is no policy entry for WMITAGPDEVCSASWITCHCOUNTSTATUSEVENT, so the parse infrastructure does not enforce a minimum length for the event struct. Additionally, the numvdevs field is taken directly from firmware and used as a loop bound over the vdevids 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 WMITAGPDEVCSASWITCHCOUNTSTATUSEVENT so the parse infrastructure enforces a minimum length for the fixed-size event struct. Add a helper ath11kwmitlvdatalen() to recover the payload length of a parsed TLV from the header preceding its data pointer. Use it in ath11kwmiprocesscsaswitchcountevent() to bound numvdevs before the loop. Compile tested only.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
Upgrade
ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
Upgrade
ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
Upgrade
ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
Upgrade
ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
Upgrade
ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
Upgrade
ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1 - Compensating control
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.
- Compensating control
Add ath11k_wmi_tlv_data_len() to recover the parsed TLV payload length from the header preceding its data pointer, and use it in ath11k_wmi_process_csa_switch_count_event() to ensure num_vdevs fits within the TLV payload before looping over vdev_ids.
Event History
Frequently Asked Questions
Which systems should be prioritized for review?
Prioritize Ubuntu systems using an affected Linux kernel package where the ath11k Wi-Fi driver is in use. The listed packages are linux, linux-realtime, linux-azure, linux-gcp, linux-azure-fde, linux-gke, linux-riscv, and linux-gkeop.
What is known about the conditions for exploitation?
The issue is triggered while processing a CSA switch-count event supplied by firmware, where an undersized TLV or an unchecked num_vdevs value can cause an out-of-bounds read. The supplied severity vector indicates adjacent attack vector, no privileges required, and no user interaction required.