In the Linux kernel, the following vulnerability has been resolved:
cnic: Fix use-after-free bugs in cnic_delete_task
The original code uses cancel_delayed_work() in cnic_cm_stop_bnx2x_hw(),
which does not guarantee that the delayed work item 'delete_task' has
fully completed if it was already running. Additionally, the delayed work
item is cyclic, the flush_workqueue() in cnic_cm_stop_bnx2x_hw() only
blocks and waits for work items that were already queued to the
workqueue prior to its invocation. Any work items submitted after
flush_workqueue() is called are not included in the set of tasks that the
flush operation awaits. This means that after the cyclic work items have
finished executing, a delayed work item may still exist in the workqueue.
This leads to use-after-free scenarios where the cnic_dev is deallocated
by cnic_free_dev(), while delete_task remains active and attempt to
dereference cnic_dev in cnic_delete_task().
A typical race condition is illustrated below:
CPU 0 (cleanup) | CPU 1 (delayed work callback)
cnic_netdev_event() |
cnic_stop_hw() | cnic_delete_task()
cnic_cm_stop_bnx2x_hw() | ...
cancel_delayed_work() | /* the queue_delayed_work()
flush_workqueue() | executes after flush_workqueue()*/
| queue_delayed_work()
cnic_free_dev(dev)//free | cnic_delete_task() //new instance
| dev = cp->dev; //use
Replace cancel_delayed_work() with cancel_delayed_work_sync() to ensure
that the cyclic delayed work item is properly canceled and that any
ongoing execution of the work item completes before the cnic_dev is
deallocated. Furthermore, since cancel_delayed_work_sync() uses
__flush_work(work, true) to synchronously wait for any currently
executing instance of the work item to finish, the flush_workqueue()
becomes redundant and should be removed.
This bug was identified through static analysis. To reproduce the issue
and validate the fix, I simulated the cnic PCI device in QEMU and
introduced intentional delays — such as inserting calls to ssleep()
within the cnic_delete_task() function — to increase the likelihood
of triggering the bug.
References
Configurations
Configuration 1 (hide)
|
History
23 Jan 2026, 20:56
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc6:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* |
|
| First Time |
Linux
Linux linux Kernel |
|
| CWE | CWE-416 | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
| References | () https://git.kernel.org/stable/c/0405055930264ea8fd26f4131466fa7652e5e47d - Patch | |
| References | () https://git.kernel.org/stable/c/0627e1481676669cae2df0d85b5ff13e7d24c390 - Patch | |
| References | () https://git.kernel.org/stable/c/6e33a7eed587062ca8161ad1f4584882a860d697 - Patch | |
| References | () https://git.kernel.org/stable/c/7b6a5b0a6b392263c3767fc945b311ea04b34bbd - Patch | |
| References | () https://git.kernel.org/stable/c/8eeb2091e72d75df8ceaa2172638d61b4cf8929a - Patch | |
| References | () https://git.kernel.org/stable/c/cfa7d9b1e3a8604afc84e9e51d789c29574fb216 - Patch | |
| References | () https://git.kernel.org/stable/c/e1fcd4a9c09feac0902a65615e866dbf22616125 - Patch | |
| References | () https://git.kernel.org/stable/c/fde6e73189f40ebcf0633aed2b68e731c25f3aa3 - Patch |
04 Oct 2025, 08:15
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2025-10-04 08:15
Updated : 2026-01-23 20:56
NVD link : CVE-2025-39945
Mitre link : CVE-2025-39945
CVE.ORG link : CVE-2025-39945
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-416
Use After Free