CVE-2026-31394
Null Pointer Dereference in Linux mac80211 AP_VLAN Handling
Publication date: 2026-04-03
Last updated on: 2026-04-03
Assigner: kernel.org
Description
Description
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | linux_kernel | * |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in the Linux kernel's mac80211 component, specifically in the ieee80211_chan_bw_change function. The function iterates over all stations and accesses certain link data via station structures. For stations on AP_VLAN interfaces, the link data is zero-initialized and does not participate in channel context reservations, leading to a NULL pointer dereference when the code tries to access channel information during a channel switch announcement (CSA). This causes a crash. The fix involves resolving the VLAN station data to its parent access point station data before accessing the link data, preventing the NULL pointer dereference.
How can this vulnerability impact me? :
This vulnerability can cause the Linux kernel to crash when handling certain wireless stations on AP_VLAN interfaces. Such a crash can lead to denial of service (DoS) conditions on affected systems, potentially disrupting network connectivity and impacting system stability.
What immediate steps should I take to mitigate this vulnerability?
The vulnerability is resolved by updating the Linux kernel to a version that includes the fix for the mac80211 crash in ieee80211_chan_bw_change for AP_VLAN stations.
Specifically, the fix involves resolving the VLAN sdata to its parent AP sdata using get_bss_sdata() before accessing link data, preventing the NULL pointer dereference.
Therefore, the immediate mitigation step is to apply the kernel update or patch that contains this fix.