NVD / CVE Program· CNA Linux

CVE-2022-50220: usbnet: Fix linkwatch use-after-free on disconnect

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: 0.24% (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 135199a2edd459d2b123144efcd7f9bcd95128e4, 635fd8953e4309b54ca6a81bed1d4a87668694f4, 7f77dcbc030c2faa6d8e8a594985eeb34018409e.

Low priority for now. Upgrade to Linux Linux 135199a2edd459d2b123144efcd7f9bcd95128e4, 635fd8953e4309b54ca6a81bed1d4a87668694f4, 7f77dcbc030c2faa6d8e8a594985eeb34018409e 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 linkwatch use-after-free on disconnect usbnet uses the work usbnet_deferred_kevent() to perform tasks which may sleep. On disconnect, completion of the work was originally awaited in ->ndo_stop(). But in 2003, that was moved to ->disconnect() by historic commit "[PATCH] USB: usbnet, prevent exotic rtnl deadlock": https://git.kernel.org/tglx/history/c/0f138bbfd83c The change was made because back then, the kernel's workqueue implementation did not allow waiting for a single work. One had to wait for completion of *all* work by calling flush_scheduled_work(), and that could deadlock when waiting for usbnet_deferred_kevent() with rtnl_mutex held in ->ndo_stop(). The commit solved one problem but created another: It causes a use-after-free in USB Ethernet drivers aqc111.c, asix_devices.c, ax88179_178a.c, ch9200.c and smsc75xx.c: * If the drivers receive a link change interrupt immediately before disconnect, they raise EVENT_LINK_RESET in their (non-sleepable) ->status() callback and schedule usbnet_deferred_kevent(). * usbnet_deferred_kevent() invokes the driver's ->link_reset() callback, which calls netif_carrier_{on,off}(). * That in turn schedules the work linkwatch_event(). Because usbnet_deferred_kevent() is awaited after unregister_netdev(), netif_carrier_{on,off}() may operate on an unregistered netdev and linkwatch_event() may run after free_netdev(), causing a use-after-free. In 2010, usbnet was changed to only wait for a single instance of usbnet_deferred_kevent() instead of *all* work by commit 23f333a2bfaf ("drivers/net: don't use flush_scheduled_work()"). Unfortunately the commit neglected to move the wait back to ->ndo_stop(). Rectify that omission at long last.

HighCVSS 7.8 · v3.1—No exploit Fix available

Memory safety

BDU:2026-01550

Published: Jun 18, 2025
Updated: Jun 17, 2026
EPSS: 0.2% · 16th percentile
CWE: CWE-416

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 31 / 40 · 7.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.2%

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 kernel2.6.38 and later · before 4.9.326
linux linux kernel4.10 and later · before 4.14.291
linux linux kernel4.15 and later · before 4.19.256
linux linux kernel4.20 and later · before 5.4.211
linux linux kernel5.5 and later · before 5.10.137
linux linux kernel5.11 and later · before 5.15.61
linux linux kernel5.16 and later · before 5.18.18
linux linux kernel5.19 and later · before 5.19.2

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
- 2.6.38affected
- 23f333a2bfafba80339315b724808982a9de57d9 and later · before d2d6b530d89b0a912148018027386aa049f0a309affected · git
- 23f333a2bfafba80339315b724808982a9de57d9 and later · before e2a521a7dcc463c5017b4426ca0804e151faeff7affected · git
- 23f333a2bfafba80339315b724808982a9de57d9 and later · before 7f77dcbc030c2faa6d8e8a594985eeb34018409eaffected · git
- 23f333a2bfafba80339315b724808982a9de57d9 and later · before 8b4588b8b00b299be16a35be67b331d8fdba03f3affected · git
- 23f333a2bfafba80339315b724808982a9de57d9 and later · before 135199a2edd459d2b123144efcd7f9bcd95128e4affected · git
- 23f333a2bfafba80339315b724808982a9de57d9 and later · before 635fd8953e4309b54ca6a81bed1d4a87668694f4affected · git
- 23f333a2bfafba80339315b724808982a9de57d9 and later · before d49bb8cf9bfaa06aa527eb30f1a52a071da2e32faffected · git
- 23f333a2bfafba80339315b724808982a9de57d9 and later · before db3b738ae5f726204876f4303c49cfdf4311403faffected · git
- 23f333a2bfafba80339315b724808982a9de57d9 and later · before a69e617e533edddf3fa3123149900f36e0a6dc74affected · git

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 6.0.2-1	6.0.2-1

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-2022-50218Jun 18, 2025 · iio: light: isl29028: Fix the warning in isl29028_remove()
22Monitor
← EarlierCVE-2022-50219Jun 18, 2025 · bpf: Fix KASAN use-after-free Read in compute_effective_progs
31Monitor
Later →CVE-2022-50221Jun 18, 2025 · drm/fb-helper: Fix out-of-bounds access
28Monitor

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	135199a2edd459d2b123144efcd7f9bcd95128e4	Vendor (CNA)
Linux Linux	635fd8953e4309b54ca6a81bed1d4a87668694f4	Vendor (CNA)
Linux Linux	7f77dcbc030c2faa6d8e8a594985eeb34018409e	Vendor (CNA)
Linux Linux	8b4588b8b00b299be16a35be67b331d8fdba03f3	Vendor (CNA)
Linux Linux	a69e617e533edddf3fa3123149900f36e0a6dc74	Vendor (CNA)
Linux Linux	d2d6b530d89b0a912148018027386aa049f0a309	Vendor (CNA)
Linux Linux	d49bb8cf9bfaa06aa527eb30f1a52a071da2e32f	Vendor (CNA)
Linux Linux	db3b738ae5f726204876f4303c49cfdf4311403f	Vendor (CNA)
Linux Linux	e2a521a7dcc463c5017b4426ca0804e151faeff7	Vendor (CNA)
debian:linux	6.0.2-1 · 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/135199a2edd459d2b123144efcd7f9bcd95128e4

Show all references (8 more)

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

All records