CVE-2022-50258 wifi: brcmfmac: Fix potential stack-out-of-bounds in brcmf_c_preinit_dcmds()
A stack-out-of-bounds read in the Linux kernel brcmfmac WiFi driver can cause a system crash when processing firmware version strings.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-50258?
CVE-2022-50258 is a high-severity memory corruption vulnerability in Linux kernel, published on 15 Sep 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmfmac: Fix potential stack-out-of-bounds in brcmf_c_preinit_dcmds()
This patch fixes a stack-out-of-bounds read in brcmfmac that occurs when 'buf' that is not null-terminated is passed as an argument of strsep() in brcmf_c_preinit_dcmds(). This buffer is filled with a firmware version string by memcpy() in brcmf_fil_iovar_data_get(). The patch ensures buf is null-terminated.
Found by a modified version of syzkaller.
[ 47.569679][ T1897] brcmfmac: brcmf_fw_alloc_request: using brcm/brcmfmac43236b for chip BCM43236/3 [ 47.582839][ T1897] brcmfmac: brcmf_c_process_clm_blob: no clm_blob available (err=-2), device may have limited channels available [ 47.601565][ T1897] ================================================================== [ 47.602574][ T1897] BUG: KASAN: stack-out-of-bounds in strsep+0x1b2/0x1f0 [ 47.603447][ T1897] Read of size 1 at addr ffffc90001f6f000 by task kworker/0:2/1897 [ 47.604336][ T1897] [ 47.604621][ T1897] CPU: 0 PID: 1897 Comm: kworker/0:2 Tainted: G O 5.14.0+ #131 [ 47.605617][ T1897] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014 [ 47.606907][ T1897] Workqueue: usb_hub_wq hub_event [ 47.607453][ T1897] Call Trace: [ 47.607801][ T1897] dump_stack_lvl+0x8e/0xd1 [ 47.608295][ T1897] print_address_description.constprop.0.cold+0xf/0x334 [ 47.609009][ T1897] ? strsep+0x1b2/0x1f0 [ 47.609434][ T1897] ? strsep+0x1b2/0x1f0 [ 47.609863][ T1897] kasan_report.cold+0x83/0xdf [ 47.610366][ T1897] ? strsep+0x1b2/0x1f0 [ 47.610882][ T1897] strsep+0x1b2/0x1f0 [ 47.611300][ T1897] ? brcmf_fil_iovar_data_get+0x3a/0xf0 [ 47.611883][ T1897] brcmf_c_preinit_dcmds+0x995/0xc40 [ 47.612434][ T1897] ? brcmf_c_set_joinpref_default+0x100/0x100 [ 47.613078][ T1897] ? rcu_read_lock_sched_held+0xa1/0xd0 [ 47.613662][ T1897] ? rcu_read_lock_bh_held+0xb0/0xb0 [ 47.614208][ T1897] ? lock_acquire+0x19d/0x4e0 [ 47.614704][ T1897] ? find_held_lock+0x2d/0x110 [ 47.615236][ T1897] ? brcmf_usb_deq+0x1a7/0x260 [ 47.615741][ T1897] ? brcmf_usb_rx_fill_all+0x5a/0xf0 [ 47.616288][ T1897] brcmf_attach+0x246/0xd40 [ 47.616758][ T1897] ? wiphy_new_nm+0x1703/0x1dd0 [ 47.617280][ T1897] ? kmemdup+0x43/0x50 [ 47.617720][ T1897] brcmf_usb_probe+0x12de/0x1690 [ 47.618244][ T1897] ? brcmf_usbdev_qinit.constprop.0+0x470/0x470 [ 47.618901][ T1897] usb_probe_interface+0x2aa/0x760 [ 47.619429][ T1897] ? usb_probe_device+0x250/0x250 [ 47.619950][ T1897] really_probe+0x205/0xb70 [ 47.620435][ T1897] ? driver_allows_async_probing+0x130/0x130 [ 47.621048][ T1897] __driver_probe_device+0x311/0x4b0 [ 47.621595][ T1897] ? driver_allows_async_probing+0x130/0x130 [ 47.622209][ T1897] driver_probe_device+0x4e/0x150 [ 47.622739][ T1897] __device_attach_driver+0x1cc/0x2a0 [ 47.623287][ T1897] bus_for_each_drv+0x156/0x1d0 [ 47.623796][ T1897] ? bus_rescan_devices+0x30/0x30 [ 47.624309][ T1897] ? lockdep_hardirqs_on_prepare+0x273/0x3e0 [ 47.624907][ T1897] ? trace_hardirqs_on+0x46/0x160 [ 47.625437][ T1897] __device_attach+0x23f/0x3a0 [ 47.625924][ T1897] ? device_bind_driver+0xd0/0xd0 [ 47.626433][ T1897] ? kobject_uevent_env+0x287/0x14b0 [ 47.627057][ T1897] bus_probe_device+0x1da/0x290 [ 47.627557][ T1897] device_add+0xb7b/0x1eb0 [ 47.628027][ T1897] ? wait_for_completion+0x290/0x290 [ 47.628593][ T1897] ? __fw_devlink_link_to_suppliers+0x5a0/0x5a0 [ 47.629249][ T1897] usb_set_configuration+0xf59/0x16f0 [ 47.629829][ T1897] usb_generic_driver_probe+0x82/0xa0 [ 47.630385][ T1897] usb_probe_device+0xbb/0x250 [ 47.630927][ T1897] ? usb_suspend+0x590/0x590 [ 47.631397][ T1897] really_probe+0x205/0xb70 [ 47.631855][ T1897] ? driver_allows_async_probing+0x130/0x130 [ 47.632469][ T1897] __driver_probe_device+0x311/0x4b0 [ 47.633002][ ---truncated---
Weakness: CWE-787
Which versions are affected by CVE-2022-50258?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2022-50258?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2022-50258 being exploited?
There is no known exploitation of CVE-2022-50258 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2022-50258, GHSA-vcqq-2g47-gfp7, UBUNTU-CVE-2022-50258.