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CVE Record

CVE-2021-47560: mlxsw: spectrum: Protect driver from buggy firmware

In the Linux kernel, the following vulnerability has been resolved: mlxsw: spectrum: Protect driver from buggy firmware When processing port up/down events generated by the device's firmware, the driver protects itself from events reported for non-existent local ports, but not the CPU port (local port 0), which exists, but lacks a netdev. This can result in a NULL pointer dereference when calling netif_carrier_{on,off}(). Fix this by bailing early when processing an event reported for the CPU port. Problem was only observed when running on top of a buggy emulator.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This is a Linux kernel driver bug in mlxsw Spectrum handling of firmware port events. A bad event for the CPU port can trigger a NULL pointer dereference. The public record gives no CVSS score and says the issue was observed only with a buggy emulator, so business urgency is limited unless this driver is used.

Executive priority

Treat as targeted maintenance, not an emergency, unless critical infrastructure uses this driver. Lack of CVSS, no KEV listing, and emulator-only observation reduce urgency, but kernel NULL dereferences can still affect availability.

Technical view

The mlxsw Spectrum driver filtered events for non-existent local ports but not local port 0, the CPU port. That port exists but has no netdev, so carrier state handling could dereference NULL. The fix exits early for CPU-port events.

Likely exposure

Likely limited to Linux systems using the mlxsw Spectrum driver, especially environments with Mellanox/NVIDIA Spectrum switching hardware or emulation. The source does not provide distribution-specific package status.

Exploitation context

No active exploitation is cited, and KEV status is false. The source describes the trigger as firmware-generated port up/down events and notes the problem was only observed on a buggy emulator.

Researcher notes

Evidence supports a defensive driver hardening fix, not a broad remotely exploitable issue. The CVE record lists Linux versions and stable commits but does not provide CVSS, CWE, exploitability details, or distribution package mappings.

Mitigation direction

  • Update affected Linux kernels to versions containing the referenced stable fixes.
  • Check Linux distribution advisories for backported fixes in shipped kernel packages.
  • Prioritize hosts using mlxsw Spectrum hardware, firmware, or emulation.
  • Follow vendor kernel guidance if no package fix is identified.

Validation and detection

  • Inventory systems loading or packaging the mlxsw Spectrum driver.
  • Compare running kernel builds against distribution advisories and referenced stable commits.
  • Review kernel logs for NULL dereference crashes around mlxsw or carrier state changes.
  • Confirm emulator or firmware test environments are covered by patched kernels.
Prepared
Confidence
medium
Sources
5

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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CVE-2021-47560 mapping review

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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
2ADP providers
4Source 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
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux28b1987ef5064dd5c43538ba1168ef7b801f3cad, 28b1987ef5064dd5c43538ba1168ef7b801f3cad, 28b1987ef5064dd5c43538ba1168ef7b801f3cadunaffected
LinuxLinux5.4, 0, 5.10.83, 5.15.6, 5.16affected
Weakness

CWE details

No CWE listed

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