In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: fix crash when unbinding
If there is an error during some initialization related to firmware, the function ath12k_dp_cc_cleanup is called to release resources. However this is released again when the device is unbinded (ath12k_pci), and we get: BUG: kernel NULL pointer dereference, address: 0000000000000020 at RIP: 0010:ath12k_dp_cc_cleanup.part.0+0xb6/0x500 [ath12k] Call Trace: ath12k_dp_cc_cleanup ath12k_dp_free ath12k_core_deinit ath12k_pci_remove ...
The issue is always reproducible from a VM because the MSI addressing initialization is failing.
In order to fix the issue, just set to NULL the released structure in ath12k_dp_cc_cleanup at the end.
Exploitability
AV:LAC:LPR:LUI:NScope
S:UImpact
C:NI:NA:H5.5/CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H