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CVE Record

CVE-2021-46909: ARM: footbridge: fix PCI interrupt mapping

In the Linux kernel, the following vulnerability has been resolved: ARM: footbridge: fix PCI interrupt mapping Since commit 30fdfb929e82 ("PCI: Add a call to pci_assign_irq() in pci_device_probe()"), the PCI code will call the IRQ mapping function whenever a PCI driver is probed. If these are marked as __init, this causes an oops if a PCI driver is loaded or bound after the kernel has initialised.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue can crash affected ARM footbridge systems when a PCI driver is loaded or bound after kernel initialization. The public record does not provide CVSS, CWE, exploitability, or broad product impact. Treat it mainly as an availability and platform-stability risk until vendor advisories clarify exposure.

Executive priority

Low urgency for most environments unless they operate ARM footbridge systems. For exposed legacy or embedded systems, handle through normal kernel maintenance because crashes could affect service availability.

Technical view

The bug is in ARM footbridge PCI interrupt mapping. After Linux commit 30fdfb929e82 made PCI probe call pci_assign_irq(), IRQ mapping functions marked __init could be called after initialization, causing a kernel oops when probing later PCI drivers.

Likely exposure

Exposure appears limited to Linux kernels on ARM footbridge platforms using affected PCI behavior. The source lists Linux kernel versions and stable commit references but does not identify distributions, packaged releases, or cloud images.

Exploitation context

CISA KEV is false, and the provided sources do not state active exploitation or public exploit availability. Triggering requires the affected platform condition: PCI driver loading or binding after kernel initialization.

Researcher notes

The record describes a kernel lifecycle annotation bug, not a memory corruption exploit path. Evidence is incomplete: no CVSS, CWE, exploit status, distribution mapping, or attacker preconditions are provided in the bundle.

Mitigation direction

  • Check Linux vendor or distribution guidance for CVE-2021-46909.
  • Update to a kernel that includes the referenced stable fix commits.
  • Prioritize ARM footbridge systems with PCI devices or dynamically loaded PCI drivers.
  • Avoid assuming non-footbridge Linux systems are affected without vendor confirmation.

Validation and detection

  • Inventory Linux kernels running on ARM footbridge hardware.
  • Check whether deployed kernel source includes one of the referenced fixes.
  • Review crash logs for kernel oops events during PCI driver probe or bind.
  • Confirm distribution advisories map this CVE to your shipped kernel package.
Prepared
Confidence
medium
Sources
8

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-2021-46909 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
7Source 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
LinuxLinux30fdfb929e82450bbf3d0e0aba56efbc29b52b52, 30fdfb929e82450bbf3d0e0aba56efbc29b52b52, 30fdfb929e82450bbf3d0e0aba56efbc29b52b52, 30fdfb929e82450bbf3d0e0aba56efbc29b52b52, 30fdfb929e82450bbf3d0e0aba56efbc29b52b52, 30fdfb929e82450bbf3d0e0aba56efbc29b52b52unaffected
LinuxLinux4.13, 0, 4.14.232, 4.19.189, 5.4.114, 5.10.32, 5.11.16, 5.12affected
Weakness

CWE details

No CWE listed

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