net: caif: Fix use-after-free in cfusbl_device_notify()
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.
- Published
- May 2, 2025
- Updated
- Aug 5, 2026
- EPSS
- 0.2% · 8th percentile
- CWE
- CWE-416
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Report tools
Action score
31
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
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.
Affected systems
| 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 recordsOther highest-scoring records for the same primary product.
- 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 KEV89Now
- CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV85Now
- CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV83Now
- CVE-2019-13272In the Linux kernel before 5.1.17, ptrace_link in kernel/ptrace.c mishandles the recording of the credentials of a process that wants to creKEV77This week
- CVE-2013-6282The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the v6k and v7 ARM platforms do not validate certain addKEV77This week
- CVE-2013-2094The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9 uses an incorrect integer data type, which allows loKEV77This 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 / 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.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
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 researchersFinders, 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 FreeCVSS 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 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
free(dev->buf);/* ... another thread is still running ... */process(dev->buf);Fixed
lock(&dev->lock);free(dev->buf);dev->buf = NULL;unlock(&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.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- git.kernel.org/stable/c/1793da97a23e31c5bf06631f3f3e5a25f368fd64
- git.kernel.org/stable/c/287027d8a567168a5d8ce5cb0cba16a34791a48c
- git.kernel.org/stable/c/3f14457e1584224f4296af613bbd99deb60b5d91
- git.kernel.org/stable/c/68a45c3cf0e2242a533657f4f535d9b6a7447a79
- git.kernel.org/stable/c/9781e98a97110f5e76999058368b4be76a788484
- git.kernel.org/stable/c/9dc16be373b382ddd4c274052a6e870a95e76c01
- git.kernel.org/stable/c/c3aaec463a632cf4187dc017e421bfa69d7834a9
- git.kernel.org/stable/c/d1a11bbdbb5ea9f172019c5a4a3e9d8eabd72179
Vendor advisories and official records. Exploit/PoC links are deliberately left out.