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CVE Record

CVE-2021-47547: net: tulip: de4x5: fix the problem that the array 'lp->phy[8]' may be out of bound

In the Linux kernel, the following vulnerability has been resolved: net: tulip: de4x5: fix the problem that the array 'lp->phy[8]' may be out of bound In line 5001, if all id in the array 'lp->phy[8]' is not 0, when the 'for' end, the 'k' is 8. At this time, the array 'lp->phy[8]' may be out of bound.

MediumCVSS 4.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-47547 is a Linux kernel bug in the tulip de4x5 network driver. A local, low-privileged user could potentially cause limited integrity or availability impact. The public record rates it medium with CVSS 4.4. No provided source says it is being actively exploited.

Executive priority

Treat as routine but real kernel maintenance. It is not internet-exploitable from the supplied evidence, but local kernel bugs can matter on shared systems, developer workstations, and servers where untrusted users or workloads run.

Technical view

The issue is an out-of-bounds access risk involving the lp->phy[8] array in the Linux kernel de4x5 driver. If all IDs in the array are nonzero, loop index k can reach 8 and access beyond the array boundary. The Linux stable commits are listed as the resolution.

Likely exposure

Exposure is most likely on Linux systems running affected kernel versions where the tulip de4x5 driver is present or relevant. The bundle lists Linux as the affected product and includes multiple stable branch fix commits, but does not identify specific distributions or appliances.

Exploitation context

The CVSS vector is local, low complexity, low privilege, no user interaction, with limited integrity and availability impact. CISA KEV status is false, and the supplied sources do not report public exploitation or exploit availability.

Researcher notes

The core condition is k reaching 8 after scanning lp->phy[8], creating an out-of-bounds reference. The source bundle does not provide proof-of-concept details, affected distribution mappings, or named mitigations beyond the stable kernel fixes.

Mitigation direction

  • Apply Linux kernel updates containing the referenced stable fixes.
  • Check your Linux distribution advisories for backported fixes.
  • Prioritize systems where the de4x5 driver is present or used.
  • If patching is delayed, request supported workaround guidance from the vendor.

Validation and detection

  • Inventory Linux kernel versions across managed hosts.
  • Check whether the tulip de4x5 driver exists or is loaded.
  • Confirm vendor kernel packages include the referenced stable fix commits.
  • Track remediation through normal kernel update and reboot processes.
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

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2021-47547 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
4.4 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/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
4.4CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:L1.82.5CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

4.4Medium
CVSS 3.1 vector shape for CVE-2021-47547Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/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
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2unaffected
LinuxLinux2.6.12, 0, 4.4.294, 4.9.292, 4.14.257, 4.19.220, 5.4.164, 5.10.84, 5.15.7, 5.16affected
Weakness

CWE details

No CWE listed

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