cbcvebase.
CVE-2025-39863
published 2025-09-19

CVE-2025-39863: In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: fix use-after-free when rescheduling brcmf_btcoex_info work The…

PriorityP340high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.15%
4.4th percentile
In the Linux kernel, the following vulnerability has been resolved: wifi: brcmfmac: fix use-after-free when rescheduling brcmf_btcoex_info work The brcmf_btcoex_detach() only shuts down the btcoex timer, if the flag timer_on is false. However, the brcmf_btcoex_timerfunc(), which runs as timer handler, sets timer_on to false. This creates critical race conditions: 1.If brcmf_btcoex_detach() is called while brcmf_btcoex_timerfunc() is executing, it may observe timer_on as false and skip the call to timer_shutdown_sync(). 2.The brcmf_btcoex_timerfunc() may then reschedule the brcmf_btcoex_info worker after the cancel_work_sync() has been executed, resulting in use-after-free bugs. The use-after-free bugs occur in two distinct scenarios, depending on the timing of when the brcmf_btcoex_info struct is freed relative to the execution of its worker thread. Scenario 1: Freed before the worker is scheduled The brcmf_btcoex_info is deallocated before the worker is scheduled. A race condition can occur when schedule_work(&bt_local->work) is called after the target memory has been freed. The sequence of events is detailed below: CPU0 | CPU1 brcmf_btcoex_detach | brcmf_btcoex_timerfunc | bt_local->timer_on = false; if (cfg->btcoex->timer_on) | ... | cancel_work_sync(); | ... | kfree(cfg->btcoex); // FREE | | schedule_work(&bt_local->work); // USE Scenario 2: Freed after the worker is scheduled The brcmf_btcoex_info is freed after the worker has been scheduled but before or during its execution. In this case, statements within the brcmf_btcoex_handler() — such as the container_of macro and subsequent dereferences of the brcmf_btcoex_info object will cause a use-after-free access. The following timeline illustrates this scenario: CPU0 | CPU1 brcmf_btcoex_detach | brcmf_btcoex_timerfunc | bt_local->timer_on = false; if (cfg->btcoex->timer_on) | ... | cancel_work_sync(); | ... | schedule_work(); // Reschedule | kfree(cfg->btcoex); // FREE | brcmf_btcoex_handler() // Worke

Affected

24 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.16.6-1 (forky)linux 6.16.6-1 (forky)
linuxlinux
linuxlinux>= 61730d4dfffc2cc9d3a49fad87633008105c18ba < c75600e69e66a751cc046cd9c407b942f298d852c75600e69e66a751cc046cd9c407b942f298d852
linuxlinux>= 61730d4dfffc2cc9d3a49fad87633008105c18ba < ae58f70bde0433f27ef4b388ab50634736607bf6ae58f70bde0433f27ef4b388ab50634736607bf6
linuxlinux>= 61730d4dfffc2cc9d3a49fad87633008105c18ba < f1150153c4e5940fe49ab51136343c5b4fe49d63f1150153c4e5940fe49ab51136343c5b4fe49d63
linuxlinux>= 61730d4dfffc2cc9d3a49fad87633008105c18ba < 3e789f8475f6c857c88de5c5bf4b24b11a477dd73e789f8475f6c857c88de5c5bf4b24b11a477dd7
linuxlinux>= 61730d4dfffc2cc9d3a49fad87633008105c18ba < 2f6fbc8e04ca1d1d5c560be694199f847229c6252f6fbc8e04ca1d1d5c560be694199f847229c625
linuxlinux>= 61730d4dfffc2cc9d3a49fad87633008105c18ba < 9cb83d4be0b9b697eae93d321e0da999f9cdfcfc9cb83d4be0b9b697eae93d321e0da999f9cdfcfc
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel>= 0 < 6.12.48-16.12.48-1
linuxlinux_kernel>= 0 < 6.16.6-16.16.6-1
linuxlinux_kernel>= 0 < 6.8.0-106.1066.8.0-106.106
linuxlinux_kernel>= 3.10 < 6.6.1056.6.105
linuxlinux_kernel>= 6.13 < 6.16.66.16.6
linuxlinux_kernel>= 6.7 < 6.12.466.12.46
msrcazl3_kernel_6.6.104.2-4_on_azure_linux_3.0
msrcazl3_kernel_6.6.96.2-2_on_azure_linux_3.0
msrccbl2_kernel_5.15.186.1-1_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.200.1-1_on_cbl_mariner_2.0
msrccbl2_kernel_5.15.202.1-1_on_cbl_mariner_2.0
ubuntulinux-xilinx

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vendor_debian7.8HIGH
vendor_msrc7.8HIGH
vendor_redhat7.8HIGH
vendor_ubuntu7.8HIGH
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