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CVE Record

CVE-2021-47498: dm rq: don't queue request to blk-mq during DM suspend

In the Linux kernel, the following vulnerability has been resolved: dm rq: don't queue request to blk-mq during DM suspend DM uses blk-mq's quiesce/unquiesce to stop/start device mapper queue. But blk-mq's unquiesce may come from outside events, such as elevator switch, updating nr_requests or others, and request may come during suspend, so simply ask for blk-mq to requeue it. Fixes one kernel panic issue when running updating nr_requests and dm-mpath suspend/resume stress test.

MediumCVSS 5.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This Linux kernel flaw can cause a system crash when device-mapper request queues are suspended while block-multiqueue settings are changed. The business impact is availability: affected servers could panic and require recovery. The provided sources do not show remote attack capability or confirmed active exploitation.

Executive priority

Treat as a scheduled but meaningful availability fix. Prioritize critical Linux storage hosts, virtualization nodes, and database platforms where a kernel panic would disrupt service. Escalate if vendor advisories identify your supported kernel line as affected.

Technical view

The issue is in Linux device mapper request handling during DM suspend. blk-mq unquiesce can be triggered by outside events such as elevator changes or nr_requests updates, allowing requests during suspend. The fix requeues instead of queueing to blk-mq, preventing a kernel panic observed in dm-mpath suspend/resume stress testing.

Likely exposure

Exposure is most relevant on Linux systems using device mapper, especially request-based DM or multipath storage paths, on affected kernel builds. Internet-facing status is not the key factor because CVSS marks attack vector as local with low privileges required.

Exploitation context

The source bundle marks KEV as false and provides no cited evidence of active exploitation. CVSS indicates local access, low attack complexity, low privileges, no user interaction, and high availability impact without confidentiality or integrity impact.

Researcher notes

Evidence supports a kernel availability bug fixed in stable commits. The provided affected-version data is sparse and unusual, so exact distribution exposure should be confirmed through vendor advisories. Do not infer remote exploitation or broad weaponization from the available sources.

Mitigation direction

  • Update affected Linux kernels using vendor-supported security updates.
  • Confirm the deployed kernel includes the referenced stable device-mapper fixes.
  • For Debian LTS systems, review the cited Debian advisory and apply applicable updates.
  • Prioritize multipath or device-mapper hosts supporting critical storage workloads.
  • Avoid direct deployment workarounds unless confirmed by vendor guidance.

Validation and detection

  • Inventory Linux kernel versions across servers and appliances.
  • Identify systems using device mapper, dm-multipath, or request-based DM queues.
  • Compare deployed kernels against vendor advisories and stable fix references.
  • Check crash logs for kernel panics during DM suspend or nr_requests changes.
  • Validate patched systems under normal storage failover and maintenance workflows.
Prepared
Confidence
medium
Sources
6

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-2021-47498 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

1CVSS vectors
3Timeline events
2ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
5.5CVSS 3.1MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H1.83.6CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

5.5Medium
CVSS 3.1 vector shape for CVE-2021-47498Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

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
cvssV3_1other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux7b17c2f7292ba1f3f98dae3f7077f9e569653276, 7b17c2f7292ba1f3f98dae3f7077f9e569653276, 7b17c2f7292ba1f3f98dae3f7077f9e569653276unaffected
LinuxLinux4.10, 0, 5.10.241, 5.14.14, 5.15affected
Weakness

CWE details

No CWE listed

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