CVE-2025-38683
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-09-04

Last updated on: 2025-11-03

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: hv_netvsc: Fix panic during namespace deletion with VF The existing code move the VF NIC to new namespace when NETDEV_REGISTER is received on netvsc NIC. During deletion of the namespace, default_device_exit_batch() >> default_device_exit_net() is called. When netvsc NIC is moved back and registered to the default namespace, it automatically brings VF NIC back to the default namespace. This will cause the default_device_exit_net() >> for_each_netdev_safe loop unable to detect the list end, and hit NULL ptr: [ 231.449420] mana 7870:00:00.0 enP30832s1: Moved VF to namespace with: eth0 [ 231.449656] BUG: kernel NULL pointer dereference, address: 0000000000000010 [ 231.450246] #PF: supervisor read access in kernel mode [ 231.450579] #PF: error_code(0x0000) - not-present page [ 231.450916] PGD 17b8a8067 P4D 0 [ 231.451163] Oops: Oops: 0000 [#1] SMP NOPTI [ 231.451450] CPU: 82 UID: 0 PID: 1394 Comm: kworker/u768:1 Not tainted 6.16.0-rc4+ #3 VOLUNTARY [ 231.452042] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 11/21/2024 [ 231.452692] Workqueue: netns cleanup_net [ 231.452947] RIP: 0010:default_device_exit_batch+0x16c/0x3f0 [ 231.453326] Code: c0 0c f5 b3 e8 d5 db fe ff 48 85 c0 74 15 48 c7 c2 f8 fd ca b2 be 10 00 00 00 48 8d 7d c0 e8 7b 77 25 00 49 8b 86 28 01 00 00 <48> 8b 50 10 4c 8b 2a 4c 8d 62 f0 49 83 ed 10 4c 39 e0 0f 84 d6 00 [ 231.454294] RSP: 0018:ff75fc7c9bf9fd00 EFLAGS: 00010246 [ 231.454610] RAX: 0000000000000000 RBX: 0000000000000002 RCX: 61c8864680b583eb [ 231.455094] RDX: ff1fa9f71462d800 RSI: ff75fc7c9bf9fd38 RDI: 0000000030766564 [ 231.455686] RBP: ff75fc7c9bf9fd78 R08: 0000000000000000 R09: 0000000000000000 [ 231.456126] R10: 0000000000000001 R11: 0000000000000004 R12: ff1fa9f70088e340 [ 231.456621] R13: ff1fa9f70088e340 R14: ffffffffb3f50c20 R15: ff1fa9f7103e6340 [ 231.457161] FS: 0000000000000000(0000) GS:ff1faa6783a08000(0000) knlGS:0000000000000000 [ 231.457707] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 231.458031] CR2: 0000000000000010 CR3: 0000000179ab2006 CR4: 0000000000b73ef0 [ 231.458434] Call Trace: [ 231.458600] <TASK> [ 231.458777] ops_undo_list+0x100/0x220 [ 231.459015] cleanup_net+0x1b8/0x300 [ 231.459285] process_one_work+0x184/0x340 To fix it, move the ns change to a workqueue, and take rtnl_lock to avoid changing the netdev list when default_device_exit_net() is using it.
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Meta Information
Published
2025-09-04
Last Modified
2025-11-03
Generated
2026-05-27
AI Q&A
2025-09-04
EPSS Evaluated
2026-05-25
NVD
Affected Vendors & Products
Showing 2 associated CPEs
Vendor Product Version / Range
linux kernel 6.1.153-1
linux kernel 5.10.244-1
Helpful Resources
Exploitability
CWE
CWE Icon
KEV
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CWE ID Description
CWE-UNKNOWN
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?

This vulnerability occurs in the Linux kernel's hv_netvsc driver, where a panic happens during the deletion of a network namespace involving a Virtual Function (VF) NIC. The issue arises because when the netvsc NIC is moved back and registered to the default namespace, it automatically brings the VF NIC back as well. This causes the kernel's device exit function to fail to detect the end of the device list, leading to a NULL pointer dereference and kernel panic. The fix involves moving the namespace change operation to a workqueue and taking a lock to prevent concurrent changes to the network device list during namespace deletion.


How can this vulnerability impact me? :

This vulnerability can cause the Linux kernel to panic and crash during network namespace deletion involving VF NICs. Such a kernel panic can lead to system instability, downtime, and potential loss of network connectivity, impacting the availability and reliability of systems using the affected Linux kernel and hv_netvsc driver.


How can this vulnerability be detected on my network or system? Can you suggest some commands?

This vulnerability can be detected by monitoring kernel logs for panic or NULL pointer dereference messages related to hv_netvsc and VF NIC namespace movements. You can check the kernel log for messages similar to: 'BUG: kernel NULL pointer dereference' or lines mentioning 'Moved VF to namespace'. Commands such as 'dmesg | grep -i "hv_netvsc"' or 'journalctl -k | grep -i "NULL pointer dereference"' can help identify if the system has experienced this issue.


What immediate steps should I take to mitigate this vulnerability?

Immediate mitigation involves updating the Linux kernel to a version where this vulnerability is fixed. The fix involves moving the namespace change to a workqueue and taking rtnl_lock to avoid concurrent netdev list changes during namespace deletion. Until the update is applied, avoid operations that trigger namespace deletion or VF NIC movements on netvsc devices to prevent kernel panic.


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