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.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4379-1 | linux-6.1 security update |
Debian DLA |
DLA-4404-1 | linux security update |
Debian DSA |
DSA-6053-1 | linux security update |
EUVD |
EUVD-2025-32383 | 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. |
Ubuntu USN |
USN-8033-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8033-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8033-3 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-8034-1 | Linux kernel (NVIDIA Tegra) vulnerabilities |
Ubuntu USN |
USN-8033-4 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-8033-5 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8034-2 | Linux kernel (NVIDIA Tegra IGX) vulnerabilities |
Ubuntu USN |
USN-8033-6 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8033-7 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8033-8 | Linux kernel (Intel IoTG) vulnerabilities |
Ubuntu USN |
USN-8095-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8095-2 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-8100-1 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8095-3 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-8095-4 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-8125-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8126-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8095-5 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-8141-1 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-8163-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8165-1 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8163-2 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8243-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8261-1 | Linux kernel (Xilinx) vulnerabilities |
Fri, 23 Jan 2026 21:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-416 | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.17:rc6:*:*:*:*:*:* |
|
| Metrics |
cvssV3_1
|
cvssV3_1
|
Mon, 06 Oct 2025 22:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| References |
| |
| Metrics |
threat_severity
|
cvssV3_1
|
Mon, 06 Oct 2025 14:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Linux
Linux linux Kernel |
|
| Vendors & Products |
Linux
Linux linux Kernel |
Sat, 04 Oct 2025 07:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Title | cnic: Fix use-after-free bugs in cnic_delete_task | |
| References |
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|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-11T21:39:27.788Z
Reserved: 2025-04-16T07:20:57.148Z
Link: CVE-2025-39945
No data.
Status : Analyzed
Published: 2025-10-04T08:15:47.613
Modified: 2026-01-23T20:56:32.720
Link: CVE-2025-39945
OpenCVE Enrichment
Updated: 2025-10-06T14:41:52Z
Debian DLA
Debian DSA
EUVD
Ubuntu USN