Bug 2391060 (CVE-2025-38509)

Summary: CVE-2025-38509 kernel: wifi: mac80211: reject VHT opmode for unsupported channel widths
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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OS: Linux   
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Description OSIDB Bzimport 2025-08-26 15:09:11 UTC 
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 ieee80211_chan_width_to_rx_bw(), leading to a WARN_ON due to
invalid input. This issue was reported by syzbot.

Reject these unsupported widths early in sta_link_apply_parameters()
when opmode_notif 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.
Comment 1 Jon Moroney 2025-08-26 16:06:40 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025081650-CVE-2025-38509-e803@gregkh/T