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CVE Record

CVE-2021-46953: ACPI: GTDT: Don't corrupt interrupt mappings on watchdow probe failure

In the Linux kernel, the following vulnerability has been resolved: ACPI: GTDT: Don't corrupt interrupt mappings on watchdow probe failure When failing the driver probe because of invalid firmware properties, the GTDT driver unmaps the interrupt that it mapped earlier. However, it never checks whether the mapping of the interrupt actially succeeded. Even more, should the firmware report an illegal interrupt number that overlaps with the GIC SGI range, this can result in an IPI being unmapped, and subsequent fireworks (as reported by Dann Frazier). Rework the driver to have a slightly saner behaviour and actually check whether the interrupt has been mapped before unmapping things.

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 destabilize affected systems during ACPI GTDT watchdog initialization. If firmware provides invalid interrupt data, the kernel may unmap an interrupt it did not correctly map, potentially disrupting inter-processor interrupts. The sources do not show active exploitation or a remote attack path.

Executive priority

Treat this as a targeted kernel reliability issue. Prioritize platforms matching the ACPI GTDT and GIC conditions, especially production systems where reboot or kernel instability would have business impact. No source supports emergency response for active exploitation.

Technical view

The ACPI GTDT driver handled probe failure incorrectly: after invalid firmware properties, it attempted to unmap an interrupt without confirming mapping success. If firmware reports an illegal interrupt number overlapping the GIC SGI range, an IPI can be unmapped, causing system instability.

Likely exposure

Exposure appears limited to Linux systems using the ACPI GTDT watchdog path, particularly platforms with GIC interrupt handling. The provided sources list Linux kernel versions as affected, but do not identify distributions, hardware models, or externally reachable attack surfaces.

Exploitation context

The bundle marks KEV as false and provides no evidence of active exploitation. The trigger described depends on invalid firmware properties and interrupt mapping behavior, so operational risk is mainly availability on affected platforms rather than confirmed remote compromise.

Researcher notes

Evidence is limited to the CVE record and Linux stable commit references. No CVSS, CWE, exploit status, affected distribution matrix, or concrete exploit preconditions are provided. Analysis should remain scoped to the GTDT probe failure and interrupt unmapping flaw.

Mitigation direction

  • Update to a vendor kernel containing the referenced stable fixes.
  • Prioritize ARM or ACPI GTDT watchdog systems with GIC interrupt controllers.
  • Check Linux distribution advisories for backported fixes.
  • Avoid direct kernel deploys without normal testing and rollback planning.

Validation and detection

  • Inventory kernel versions on systems using ACPI GTDT watchdog support.
  • Confirm whether vendor kernels include the referenced upstream stable commits.
  • Review boot logs for GTDT watchdog probe failures or interrupt mapping errors.
  • Validate patched systems boot cleanly and maintain normal interrupt behavior.
Prepared
Confidence
medium
Sources
9

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-2021-46953 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
8Source 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

CVECVE Program Container
CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxca9ae5ec4ef0ed13833b03297ab319676965492c, ca9ae5ec4ef0ed13833b03297ab319676965492c, ca9ae5ec4ef0ed13833b03297ab319676965492c, ca9ae5ec4ef0ed13833b03297ab319676965492c, ca9ae5ec4ef0ed13833b03297ab319676965492c, ca9ae5ec4ef0ed13833b03297ab319676965492c, ca9ae5ec4ef0ed13833b03297ab319676965492cunaffected
LinuxLinux4.12, 0, 4.14.233, 4.19.191, 5.4.118, 5.10.36, 5.11.20, 5.12.3, 5.13affected
Weakness

CWE details

No CWE listed

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