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CVE Record

CVE-2021-47440: net: encx24j600: check error in devm_regmap_init_encx24j600

In the Linux kernel, the following vulnerability has been resolved: net: encx24j600: check error in devm_regmap_init_encx24j600 devm_regmap_init may return error which caused by like out of memory, this will results in null pointer dereference later when reading or writing register: general protection fault in encx24j600_spi_probe KASAN: null-ptr-deref in range [0x0000000000000090-0x0000000000000097] CPU: 0 PID: 286 Comm: spi-encx24j600- Not tainted 5.15.0-rc2-00142-g9978db750e31-dirty #11 9c53a778c1306b1b02359f3c2bbedc0222cba652 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014 RIP: 0010:regcache_cache_bypass drivers/base/regmap/regcache.c:540 Code: 54 41 89 f4 55 53 48 89 fb 48 83 ec 08 e8 26 94 a8 fe 48 8d bb a0 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 4a 03 00 00 4c 8d ab b0 00 00 00 48 8b ab a0 00 RSP: 0018:ffffc900010476b8 EFLAGS: 00010207 RAX: dffffc0000000000 RBX: fffffffffffffff4 RCX: 0000000000000000 RDX: 0000000000000012 RSI: ffff888002de0000 RDI: 0000000000000094 RBP: ffff888013c9a000 R08: 0000000000000000 R09: fffffbfff3f9cc6a R10: ffffc900010476e8 R11: fffffbfff3f9cc69 R12: 0000000000000001 R13: 000000000000000a R14: ffff888013c9af54 R15: ffff888013c9ad08 FS: 00007ffa984ab580(0000) GS:ffff88801fe00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055a6384136c8 CR3: 000000003bbe6003 CR4: 0000000000770ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: encx24j600_spi_probe drivers/net/ethernet/microchip/encx24j600.c:459 spi_probe drivers/spi/spi.c:397 really_probe drivers/base/dd.c:517 __driver_probe_device drivers/base/dd.c:751 driver_probe_device drivers/base/dd.c:782 __device_attach_driver drivers/base/dd.c:899 bus_for_each_drv drivers/base/bus.c:427 __device_attach drivers/base/dd.c:971 bus_probe_device drivers/base/bus.c:487 device_add drivers/base/core.c:3364 __spi_add_device drivers/spi/spi.c:599 spi_add_device drivers/spi/spi.c:641 spi_new_device drivers/spi/spi.c:717 new_device_store+0x18c/0x1f1 [spi_stub 4e02719357f1ff33f5a43d00630982840568e85e] dev_attr_store drivers/base/core.c:2074 sysfs_kf_write fs/sysfs/file.c:139 kernfs_fop_write_iter fs/kernfs/file.c:300 new_sync_write fs/read_write.c:508 (discriminator 4) vfs_write fs/read_write.c:594 ksys_write fs/read_write.c:648 do_syscall_64 arch/x86/entry/common.c:50 entry_SYSCALL_64_after_hwframe arch/x86/entry/entry_64.S:113 Add error check in devm_regmap_init_encx24j600 to avoid this situation.

LowCVSS 2.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysislow

Security readout for executives and security teams

Plain-English summary

CVE-2021-47440 is a low-severity Linux kernel bug in the Microchip encx24j600 Ethernet driver. If an internal register-map initialization fails, the driver may still continue and crash during device probing. The expected business impact is localized availability loss, not data theft or remote compromise.

Executive priority

Handle through normal kernel maintenance unless the organization operates affected embedded Linux devices. Escalate only where local privileged users can trigger driver probing on important systems or where appliance uptime is critical.

Technical view

The encx24j600 SPI probe path did not check errors from devm_regmap_init_encx24j600. A failed allocation or similar error could later be dereferenced in register access paths, producing a kernel general protection fault. The CVSS vector is local, low complexity, high privileges, no confidentiality or integrity impact, and low availability impact.

Likely exposure

Exposure is likely limited to Linux systems using or probing the encx24j600 Ethernet driver, commonly embedded or specialized hardware contexts. The source lists Linux kernel stable lines around 4.4 through 5.15-era releases as affected. Systems without this driver present, enabled, or reachable for probing are less likely to be exposed.

Exploitation context

The source bundle does not identify active exploitation, public exploit use, or KEV listing. The CVSS vector requires local access with high privileges. The documented failure mode is a kernel crash during SPI driver probing after an initialization error, so practical risk is mainly local denial of service.

Researcher notes

The evidence supports a local, privileged availability issue caused by missing error handling in a specific Linux network driver probe path. The bundle includes multiple upstream stable commit references, but does not provide distribution-specific package versions or proof of exploitation.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable Linux fixes.
  • Prioritize embedded systems that use Microchip encx24j600 Ethernet hardware.
  • Disable or avoid loading the encx24j600 driver if it is unnecessary.
  • Track distribution advisories for backported fixes on supported kernel branches.

Validation and detection

  • Inventory systems for Linux kernels in the source-listed affected ranges.
  • Check whether the encx24j600 driver is built, loaded, or configured.
  • Confirm the applicable stable fix commit is present in the running kernel source package.
  • Review kernel crash logs for encx24j600_spi_probe or regcache_cache_bypass faults.
Prepared
Confidence
high
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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ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-476: Exact CWE lookup

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cve · low confidence lookup

CVE-2021-47440 mapping review

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Vulnerability profileCVE Program record
Severity
Low
CVSS
2.3 (3.1)
Known Exploited
No
Published

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

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.

1CVSS vectors
3Timeline events
2ADP providers
9Source links

SSVC decision data

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

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
2.3CVSS 3.1LowCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L0.81.4CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

2.3Low
CVSS 3.1 vector shape for CVE-2021-47440Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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
cvssV3_1other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux04fbfce7a222327b97ca165294ef19f0faa45960, 04fbfce7a222327b97ca165294ef19f0faa45960, 04fbfce7a222327b97ca165294ef19f0faa45960, 04fbfce7a222327b97ca165294ef19f0faa45960, 04fbfce7a222327b97ca165294ef19f0faa45960, 04fbfce7a222327b97ca165294ef19f0faa45960, 04fbfce7a222327b97ca165294ef19f0faa45960, 04fbfce7a222327b97ca165294ef19f0faa45960unaffected
LinuxLinux4.4, 0, 4.4.290, 4.9.288, 4.14.252, 4.19.213, 5.4.155, 5.10.75, 5.14.14, 5.15affected
Weakness

CWE details

CWE-476

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-476 · source CWE mapping

NULL Pointer Dereference

NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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