NVD / CVE Program· CNA Linux

CVE-2023-53138: net: caif: Fix use-after-free in cfusbl_device_notify()

Noroxi assessment

Priority: Monitor (action score 31/100)

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 1793da97a23e31c5bf06631f3f3e5a25f368fd64, 287027d8a567168a5d8ce5cb0cba16a34791a48c, 3f14457e1584224f4296af613bbd99deb60b5d91.

Low priority for now. Upgrade to Linux Linux 1793da97a23e31c5bf06631f3f3e5a25f368fd64, 287027d8a567168a5d8ce5cb0cba16a34791a48c, 3f14457e1584224f4296af613bbd99deb60b5d91 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: net: caif: Fix use-after-free in cfusbl_device_notify() syzbot reported use-after-free in cfusbl_device_notify() [1]. This causes a stack trace like below: BUG: KASAN: use-after-free in cfusbl_device_notify+0x7c9/0x870 net/caif/caif_usb.c:138 Read of size 8 at addr ffff88807ac4e6f0 by task kworker/u4:6/1214 CPU: 0 PID: 1214 Comm: kworker/u4:6 Not tainted 5.19.0-rc3-syzkaller-00146-g92f20ff72066 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description.constprop.0.cold+0xeb/0x467 mm/kasan/report.c:313 print_report mm/kasan/report.c:429 [inline] kasan_report.cold+0xf4/0x1c6 mm/kasan/report.c:491 cfusbl_device_notify+0x7c9/0x870 net/caif/caif_usb.c:138 notifier_call_chain+0xb5/0x200 kernel/notifier.c:87 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:1945 call_netdevice_notifiers_extack net/core/dev.c:1983 [inline] call_netdevice_notifiers net/core/dev.c:1997 [inline] netdev_wait_allrefs_any net/core/dev.c:10227 [inline] netdev_run_todo+0xbc0/0x10f0 net/core/dev.c:10341 default_device_exit_batch+0x44e/0x590 net/core/dev.c:11334 ops_exit_list+0x125/0x170 net/core/net_namespace.c:167 cleanup_net+0x4ea/0xb00 net/core/net_namespace.c:594 process_one_work+0x996/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:302 </TASK> When unregistering a net device, unregister_netdevice_many_notify() sets the device's reg_state to NETREG_UNREGISTERING, calls notifiers with NETDEV_UNREGISTER, and adds the device to the todo list. Later on, devices in the todo list are processed by netdev_run_todo(). netdev_run_todo() waits devices' reference count become 1 while rebdoadcasting NETDEV_UNREGISTER notification. When cfusbl_device_notify() is called with NETDEV_UNREGISTER multiple times, the parent device might be freed. This could cause UAF. Processing NETDEV_UNREGISTER multiple times also causes inbalance of reference count for the module. This patch fixes the issue by accepting only first NETDEV_UNREGISTER notification.

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

BDU:2026-03859

Published: May 2, 2025
Updated: Aug 5, 2026
EPSS: 0.1% · 9th percentile
CWE: CWE-416

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CNA vs NVD score

NVD: 7.8
CNA · Linux: 7.8; agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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

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Noroxi analysis

What does it mean in your environment?

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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.

Vendor	Product	CPE
linux	linux kernel	cpe:2.3:o:linux:linux_kernel

Affected versions

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

linux linux kernel3.3 and later · before 4.14.310
linux linux kernel4.15 and later · before 4.19.278
linux linux kernel4.20 and later · before 5.4.237
linux linux kernel5.5 and later · before 5.10.175
linux linux kernel5.11 and later · before 5.15.103
linux linux kernel5.16 and later · before 6.1.20
linux linux kernel6.2 and later · before 6.2.7
linux linux kernel6.3

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
- 3.3affected
- 7ad65bf68d705b445ef10b77ab50dab22be185ee and later · before 68a45c3cf0e2242a533657f4f535d9b6a7447a79affected · git
- 7ad65bf68d705b445ef10b77ab50dab22be185ee and later · before 1793da97a23e31c5bf06631f3f3e5a25f368fd64affected · git
- 7ad65bf68d705b445ef10b77ab50dab22be185ee and later · before 9dc16be373b382ddd4c274052a6e870a95e76c01affected · git
- 7ad65bf68d705b445ef10b77ab50dab22be185ee and later · before c3aaec463a632cf4187dc017e421bfa69d7834a9affected · git
- 7ad65bf68d705b445ef10b77ab50dab22be185ee and later · before 3f14457e1584224f4296af613bbd99deb60b5d91affected · git
- 7ad65bf68d705b445ef10b77ab50dab22be185ee and later · before 287027d8a567168a5d8ce5cb0cba16a34791a48caffected · git
- 7ad65bf68d705b445ef10b77ab50dab22be185ee and later · before d1a11bbdbb5ea9f172019c5a4a3e9d8eabd72179affected · git
- 7ad65bf68d705b445ef10b77ab50dab22be185ee and later · before 9781e98a97110f5e76999058368b4be76a788484affected · git
- before 3.3not affected · semver

Package-level exposure

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

Ecosystem	Package	Affected range	Fix
Debian:12	linux	before 6.1.20-1	6.1.20-1

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-2023-53135May 2, 2025 · riscv: Use READ_ONCE_NOCHECK in imprecise unwinding stack mode
28Monitor
← EarlierCVE-2023-53136May 2, 2025 · af_unix: fix struct pid leaks in OOB support
28Monitor
Later →CVE-2023-53139May 2, 2025 · nfc: fdp: add null check of devm_kmalloc_array in fdp_nci_i2c_read_device_properties
22Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
Linux Linux	1793da97a23e31c5bf06631f3f3e5a25f368fd64	Vendor (CNA)
Linux Linux	287027d8a567168a5d8ce5cb0cba16a34791a48c	Vendor (CNA)
Linux Linux	3f14457e1584224f4296af613bbd99deb60b5d91	Vendor (CNA)
Linux Linux	68a45c3cf0e2242a533657f4f535d9b6a7447a79	Vendor (CNA)
Linux Linux	9781e98a97110f5e76999058368b4be76a788484	Vendor (CNA)
Linux Linux	9dc16be373b382ddd4c274052a6e870a95e76c01	Vendor (CNA)
Linux Linux	c3aaec463a632cf4187dc017e421bfa69d7834a9	Vendor (CNA)
Linux Linux	d1a11bbdbb5ea9f172019c5a4a3e9d8eabd72179	Vendor (CNA)
debian:linux	6.1.20-1 · Debian:12	Package 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: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Local
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-416 · Use After Free

CVSS vector

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

nvd-primary

Root cause

After a memory region is freed, another reference pointing to it is still used. By then, the same region may have been allocated for different data.

The bug in code

The whole CWE-416 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1free(dev->buf);
2/* ... another thread is still running ... */
3process(dev->buf);

Fixed

1lock(&dev->lock);
2free(dev->buf);
3dev->buf = NULL;
4unlock(&dev->lock);

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

Fix✗ → ✓Sep 28, 2026, 10:10 PM UTC

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

References

git.kernel.org/stable/c/1793da97a23e31c5bf06631f3f3e5a25f368fd64

Show all references (7 more)

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

All records