LiveActive security incident?Get immediate response
CVE Record

CVE-2021-46918: dmaengine: idxd: clear MSIX permission entry on shutdown

In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: clear MSIX permission entry on shutdown Add disabling/clearing of MSIX permission entries on device shutdown to mirror the enabling of the MSIX entries on probe. Current code left the MSIX enabled and the pasid entries still programmed at device shutdown.

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This Linux kernel issue affects shutdown handling for the idxd DMA engine driver. The kernel failed to clear MSI-X permission and PASID programming when the device shut down. Business urgency depends on whether affected kernels and compatible idxd hardware are present. No source states active exploitation or a known public exploit.

Executive priority

Prioritize as a kernel hygiene and asset-scoping item, not an emergency, unless your fleet uses affected idxd-capable systems. The missing CVSS and exploit evidence mean urgency should be driven by exposure confirmation and normal kernel patch cycles.

Technical view

The vulnerability is in Linux kernel dmaengine idxd shutdown logic. The fix clears MSI-X permission entries on shutdown to mirror setup during probe, because prior code left MSI-X enabled and PASID entries programmed. The source bundle does not provide CVSS, CWE, attack prerequisites, or impact details beyond this driver state cleanup.

Likely exposure

Exposure appears limited to Linux systems running affected kernel versions with the idxd driver and relevant hardware support. The bundle references Linux 5.11 and 5.12-era affected data, but distribution backports may change practical exposure. Confirm against vendor kernel advisories.

Exploitation context

The CVE is not listed as KEV in the provided bundle, and no cited source states active exploitation. The available evidence describes a kernel shutdown-state bug, not a demonstrated attack path. Treat exploitability and impact as unconfirmed from these sources.

Researcher notes

The source bundle is sparse: it names the fixed behavior but omits impact analysis, CVSS, CWE, and attack conditions. Research should focus on mapping affected upstream commits to distro kernels and determining whether residual MSI-X/PASID state has a security-relevant consequence on deployed hardware.

Mitigation direction

  • Apply vendor kernel updates that include the referenced stable fixes.
  • Review Linux distribution advisories for CVE-2021-46918 backport status.
  • If patching is delayed, determine whether idxd hardware and driver support are used.
  • Follow vendor guidance for any temporary operational mitigations.
  • Avoid relying on upstream version numbers alone for distro kernels.

Validation and detection

  • Inventory Linux kernel versions across affected server and workstation fleets.
  • Check vendor changelogs for CVE-2021-46918 or the stable commit references.
  • Confirm whether the idxd driver is enabled or relevant hardware is present.
  • Prioritize validation on systems using advanced DMA acceleration features.
  • Document systems where distro backports already include the fix.
Prepared
Confidence
medium
Sources
4

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

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2021-46918 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
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
3Source 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
LinuxLinux8e50d392652f20616a136165dff516b86baf5e49, 8e50d392652f20616a136165dff516b86baf5e49unaffected
LinuxLinux5.11, 0, 5.11.16, 5.12affected
Weakness

CWE details

No CWE listed

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