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CVE Record

CVE-2022-49021: net: phy: fix null-ptr-deref while probe() failed

In the Linux kernel, the following vulnerability has been resolved: net: phy: fix null-ptr-deref while probe() failed I got a null-ptr-deref report as following when doing fault injection test: BUG: kernel NULL pointer dereference, address: 0000000000000058 Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 1 PID: 253 Comm: 507-spi-dm9051 Tainted: G B N 6.1.0-rc3+ Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:klist_put+0x2d/0xd0 Call Trace: <TASK> klist_remove+0xf1/0x1c0 device_release_driver_internal+0x23e/0x2d0 bus_remove_device+0x1bd/0x240 device_del+0x357/0x770 phy_device_remove+0x11/0x30 mdiobus_unregister+0xa5/0x140 release_nodes+0x6a/0xa0 devres_release_all+0xf8/0x150 device_unbind_cleanup+0x19/0xd0 //probe path: phy_device_register() device_add() phy_connect phy_attach_direct() //set device driver probe() //it's failed, driver is not bound device_bind_driver() // probe failed, it's not called //remove path: phy_device_remove() device_del() device_release_driver_internal() __device_release_driver() //dev->drv is not NULL klist_remove() <- knode_driver is not added yet, cause null-ptr-deref In phy_attach_direct(), after setting the 'dev->driver', probe() fails, device_bind_driver() is not called, so the knode_driver->n_klist is not set, then it causes null-ptr-deref in __device_release_driver() while deleting device. Fix this by setting dev->driver to NULL in the error path in phy_attach_direct().

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can crash a system when a PHY network device probe fails in a specific driver path. It was reported from fault-injection testing, not real-world attacks. Business impact is mainly availability risk for affected Linux systems, especially embedded or networking equipment using PHY devices.

Executive priority

Handle through normal kernel patch management unless affected systems are critical network infrastructure or show related crashes. There is no source evidence of active exploitation, but unplanned kernel crashes can still affect availability.

Technical view

The bug is a NULL pointer dereference in the Linux PHY attach/remove flow. phy_attach_direct sets dev->driver before probe succeeds; if probe fails, device_bind_driver is not called, leaving knode_driver uninitialized. Later device removal can call klist_remove through __device_release_driver and dereference NULL. The fix clears dev->driver on the error path.

Likely exposure

Exposure appears limited to affected Linux kernel versions and systems exercising the PHY device attach path where probe fails. The bundle does not identify a remotely reachable attack surface, specific distributions, or affected hardware beyond Linux PHY handling.

Exploitation context

The source describes discovery during fault-injection testing. KEV is false, and the provided sources do not claim active exploitation, public exploit availability, or weaponized use. Treat it as a reliability and denial-of-service concern unless vendor guidance says otherwise.

Researcher notes

Evidence is strongest for the root cause and patch direction, but incomplete for exploitability. The CVE data has no CVSS, CWE, distribution matrix, or hardware-specific scope. Validate against exact downstream kernel backports rather than upstream version strings alone.

Mitigation direction

  • Apply Linux stable kernel updates containing the referenced PHY fix commits.
  • Check distribution or device-vendor advisories for backported kernel packages.
  • Prioritize Linux-based networking and embedded systems with PHY devices.
  • Avoid direct wrangler-style deploy assumptions; follow vendor kernel maintenance procedures.
  • If patch timing is constrained, monitor for PHY probe failures and kernel oops events.

Validation and detection

  • Inventory Linux kernel versions across servers, appliances, and embedded devices.
  • Compare deployed kernels against the affected versions and referenced stable commits.
  • Confirm package changelogs include the PHY null-pointer dereference fix.
  • Review kernel logs for PHY probe failures, device removal errors, or oops traces.
  • After updating, validate boot and network-interface initialization on representative hardware.
Prepared
Confidence
medium
Sources
10

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
1ADP providers
9Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxe13934563db047043ccead26412f552375cea90c, e13934563db047043ccead26412f552375cea90c, e13934563db047043ccead26412f552375cea90c, e13934563db047043ccead26412f552375cea90c, e13934563db047043ccead26412f552375cea90c, e13934563db047043ccead26412f552375cea90c, e13934563db047043ccead26412f552375cea90c, e13934563db047043ccead26412f552375cea90cunaffected
LinuxLinux2.6.14, 0, 4.9.335, 4.14.301, 4.19.268, 5.4.226, 5.10.158, 5.15.82, 6.0.12, 6.1affected
Weakness

CWE details

No CWE listed

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