CVE-2021-46909

Kernel crash via discarded Footbridge IRQ callbacks

Published Feb 27, 2024 · Updated May 11, 2026

Improper exception handling in Linux allows local users to crash affected ARM Footbridge systems by probing a PCI driver after boot. The Footbridge PCI IRQ mapping callbacks remain registered after their __init code has been discarded, so pci_assign_irq() can call freed initialization text. Exploitation requires an ARM Footbridge configuration and a post-initialization PCI driver load or bind; the result is a kernel oops and service interruption.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper exception handling in Linux allows local users to crash affected ARM Footbridge systems by probing a PCI driver after boot. The Footbridge PCI IRQ mapping callbacks remain registered after their __init code has been discarded, so pci_assign_irq() can call freed initialization text. Exploitation requires an ARM Footbridge configuration and a post-initialization PCI driver load or bind; the result is a kernel oops and service interruption.

The record

CVE
CVE-2021-46909
Published
Feb 27, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-754, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <1fc087fdb98d556b416c82ed6e3964a30885f47a
  2. Affected versionversion=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <2643da6aa57920d9159a1a579fb04f89a2b0d29a
  3. Affected versionversion=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <30e3b4f256b4e366a61658c294f6a21b8626dda7
  4. Affected versionversion=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <532747fd5c7aaa17ee5cf79f3e947c31eb0e35cf
  5. Affected versionversion=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <871b569a3e67f570df9f5ba195444dc7c621293b
  6. Affected versionversion=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <c3efce8cc9807339633ee30e39882f4c8626ee1d
  7. Affected versionversion=4.13

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <1fc087fdb98d556b416c82ed6e3964a30885f47a; version=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <2643da6aa57920d9159a1a579fb04f89a2b0d29a; version=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <30e3b4f256b4e366a61658c294f6a21b8626dda7; version=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <532747fd5c7aaa17ee5cf79f3e947c31eb0e35cf; version=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <871b569a3e67f570df9f5ba195444dc7c621293b; version=30fdfb929e82450bbf3d0e0aba56efbc29b52b52 <c3efce8cc9807339633ee30e39882f4c8626ee1d; version=4.13

Published CVSS scores

4.4Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-754Improper Check for Unusual or Exceptional Conditions
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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