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NVD / CVE Program· CNA Linux

CVE-2025-40164: usbnet: Fix using smp_processor_id() in preemptible code warnings

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.19% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 0134c7bff14bd50314a4f92b182850ddfc38e255, 17fbad93879e87a334062882b45fa727ba1b3dd7, 327cd4b68b4398b6c24f10eb2b2533ffbfc10185; azl3 kernel 6.6.121.1-1 on Azure Linux 3.0 6.6.126.1-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1.

Low priority for now. Upgrade to Linux Linux 0134c7bff14bd50314a4f92b182850ddfc38e255, 17fbad93879e87a334062882b45fa727ba1b3dd7, 327cd4b68b4398b6c24f10eb2b2533ffbfc10185; azl3 kernel 6.6.121.1-1 on Azure Linux 3.0 6.6.126.1-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: usbnet: Fix using smp_processor_id() in preemptible code warnings Syzbot reported the following warning: BUG: using smp_processor_id() in preemptible [00000000] code: dhcpcd/2879 caller is usbnet_skb_return+0x74/0x490 drivers/net/usb/usbnet.c:331 CPU: 1 UID: 0 PID: 2879 Comm: dhcpcd Not tainted 6.15.0-rc4-syzkaller-00098-g615dca38c2ea #0 PREEMPT(voluntary) Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:120 check_preemption_disabled+0xd0/0xe0 lib/smp_processor_id.c:49 usbnet_skb_return+0x74/0x490 drivers/net/usb/usbnet.c:331 usbnet_resume_rx+0x4b/0x170 drivers/net/usb/usbnet.c:708 usbnet_change_mtu+0x1be/0x220 drivers/net/usb/usbnet.c:417 __dev_set_mtu net/core/dev.c:9443 [inline] netif_set_mtu_ext+0x369/0x5c0 net/core/dev.c:9496 netif_set_mtu+0xb0/0x160 net/core/dev.c:9520 dev_set_mtu+0xae/0x170 net/core/dev_api.c:247 dev_ifsioc+0xa31/0x18d0 net/core/dev_ioctl.c:572 dev_ioctl+0x223/0x10e0 net/core/dev_ioctl.c:821 sock_do_ioctl+0x19d/0x280 net/socket.c:1204 sock_ioctl+0x42f/0x6a0 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x260 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f For historical and portability reasons, the netif_rx() is usually run in the softirq or interrupt context, this commit therefore add local_bh_disable/enable() protection in the usbnet_resume_rx().

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Nov 12, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 9th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel4.7.1 and later · before 5.15.199
  • linux linux kernel5.16 and later · before 6.1.162
  • linux linux kernel6.2 and later · before 6.6.122
  • linux linux kernel6.7 and later · before 6.12.64
  • linux linux kernel6.13 and later · before 6.17.5
  • linux linux kernel4.7
  • linux linux kernel6.18

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 4.7affected
    • 43daa96b166c3cf5ff30dfac0c5efa2620e4beab and later · before 6635e52bc4165793aefd686962d912d73d323afeaffected · git
    • 43daa96b166c3cf5ff30dfac0c5efa2620e4beab and later · before 65d04291adf7c59338f87aab9c6fe0bfa9993e64affected · git
    • 43daa96b166c3cf5ff30dfac0c5efa2620e4beab and later · before f45fffae5e2549bd0a4670cc52a15ad54c9f121eaffected · git
    • 43daa96b166c3cf5ff30dfac0c5efa2620e4beab and later · before 17fbad93879e87a334062882b45fa727ba1b3dd7affected · git
    • 43daa96b166c3cf5ff30dfac0c5efa2620e4beab and later · before d1944bab8e0c1511f0cbf364aa06547735bb0ddbaffected · git
    • 43daa96b166c3cf5ff30dfac0c5efa2620e4beab and later · before 0134c7bff14bd50314a4f92b182850ddfc38e255affected · git
    • 43daa96b166c3cf5ff30dfac0c5efa2620e4beab and later · before 327cd4b68b4398b6c24f10eb2b2533ffbfc10185affected · git
    • before 4.7not affected · semver
    • 5.10.259 and later · up to and including 5.10.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.162-16.1.162-1
Debian:13linuxbefore 6.12.69-16.12.69-1
Debian:14linuxbefore 6.17.6-16.17.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-40090Oct 30, 2025 · ksmbd: fix recursive locking in RPC handle list access
    22Monitor
  • ← EarlierCVE-2025-40149Nov 12, 2025 · tls: Use __sk_dst_get() and dst_dev_rcu() in get_netdev_for_sock().
    31Monitor
  • Later →CVE-2025-13315Nov 19, 2025 · Unauthenticated log access in Twonky Server
    60This week

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0134c7bff14bd50314a4f92b182850ddfc38e255Vendor (CNA)
Linux Linux17fbad93879e87a334062882b45fa727ba1b3dd7Vendor (CNA)
Linux Linux327cd4b68b4398b6c24f10eb2b2533ffbfc10185Vendor (CNA)
Linux Linux65d04291adf7c59338f87aab9c6fe0bfa9993e64Vendor (CNA)
Linux Linux6635e52bc4165793aefd686962d912d73d323afeVendor (CNA)
Linux Linuxd1944bab8e0c1511f0cbf364aa06547735bb0ddbVendor (CNA)
Linux Linuxf45fffae5e2549bd0a4670cc52a15ad54c9f121eVendor (CNA)
azl3 kernel 6.6.121.1-1 on Azure Linux 3.06.6.126.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.05.15.200.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.162-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records