CVE-2025-38509: wifi: mac80211: reject VHT opmode for unsupported channel widths
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: reject VHT opmode for unsupported channel widths
VHT operating mode notifications are not defined for channel widths below 20 MHz. In particular, 5 MHz and 10 MHz are not valid under the VHT specification and must be rejected.
Without this check, malformed notifications using these widths may reach ieee80211chanwidthtorxbw(), leading to a WARNON due to invalid input. This issue was reported by syzbot.
Reject these unsupported widths early in stalinkapplyparameters() when opmodenotif is used. The accepted set includes 20, 40, 80, 160, and 80+80 MHz, which are valid for VHT. While 320 MHz is not defined for VHT, it is allowed to avoid rejecting HE or EHT clients that may still send a VHT opmode notification.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
linux/Kernelto a version that resolves this vulnerability.Fixed in 6.15.7 - Upgrade
Upgrade
ubuntu/linux-aws-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1017.17~24.04.1 - Upgrade
Upgrade
ubuntu/linux-azure-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1017.17~24.04.1 - Upgrade
Upgrade
ubuntu/linux-gcp-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1020.21~24.04.1 - Upgrade
Upgrade
ubuntu/linux-oem-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1016.16 - Upgrade
Upgrade
ubuntu/linux-oracle-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1017.17~24.04.1 - Upgrade
Upgrade
ubuntu/linux-riscv-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-36.36.1~24.04.1 - Upgrade
Upgrade
ubuntu/linux-realtime-6.14to a version that resolves this vulnerability.Fixed in 6.14.0-1016.16~24.04.1
Event History
Frequently Asked Questions
What is the severity of CVE-2025-38509?
CVE-2025-38509 is classified as a medium severity vulnerability in the Linux kernel.
How do I fix CVE-2025-38509?
To fix CVE-2025-38509, users should update to the latest patched version of the Linux kernel that addresses this vulnerability.
What does CVE-2025-38509 affect?
CVE-2025-38509 affects the Linux kernel's handling of VHT operating mode notifications for unsupported channel widths.
Is CVE-2025-38509 a remote exploit?
CVE-2025-38509 does not appear to be a remote exploit but rather pertains to local kernel operations.
Who is impacted by CVE-2025-38509?
Users and developers relying on Linux kernel versions that have not been updated to include the fix for CVE-2025-38509 are impacted.