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CVE Record

CVE-2021-47075: nvmet: fix memory leak in nvmet_alloc_ctrl()

In the Linux kernel, the following vulnerability has been resolved: nvmet: fix memory leak in nvmet_alloc_ctrl() When creating ctrl in nvmet_alloc_ctrl(), if the cntlid_min is larger than cntlid_max of the subsystem, and jumps to the "out_free_changed_ns_list" label, but the ctrl->sqs lack of be freed. Fix this by jumping to the "out_free_sqs" label.

MediumCVSS 5.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-47075 is a Linux kernel memory leak in the NVMe target code. Under a specific controller allocation failure path, memory is not freed. The practical business impact is potential low availability degradation on affected systems, especially where Linux is used as an NVMe target service.

Executive priority

Treat this as a moderate availability risk, not a data theft issue. Patch through normal kernel maintenance, with higher priority for storage target hosts or environments where availability degradation would disrupt business services.

Technical view

The flaw is in nvmet_alloc_ctrl(). If a subsystem has cntlid_min greater than cntlid_max, execution jumps to out_free_changed_ns_list and misses freeing ctrl->sqs. The CVSS vector indicates remote, unauthenticated reachability with low availability impact and no confidentiality or integrity impact.

Likely exposure

Exposure is most relevant to Linux systems running affected kernels with NVMe target functionality enabled or reachable. The source lists Linux kernel versions around 5.7 through fixed stable updates, but operators must map distribution kernel packages to the cited upstream fixes.

Exploitation context

The bundle does not show CISA KEV listing or cited evidence of active exploitation. The CVSS vector allows network, unauthenticated interaction, but the provided sources only describe the memory leak and fix, not public exploitation.

Researcher notes

The source evidence is narrow and kernel-specific. It supports a memory leak in an error path and upstream stable fixes. It does not provide exploit details, affected distribution package names, or evidence of real-world exploitation.

Mitigation direction

  • Apply vendor kernel updates that include the cited stable fixes.
  • Prioritize systems providing NVMe target services or shared storage infrastructure.
  • If immediate patching is unavailable, check vendor guidance for temporary risk reduction.
  • Confirm distribution advisories before assuming upstream version numbers map directly.

Validation and detection

  • Inventory Linux kernel versions across storage and infrastructure hosts.
  • Identify systems with NVMe target functionality enabled or exposed.
  • Verify patched kernels include the cited stable commits or vendor backports.
  • Monitor affected systems for abnormal memory growth or availability degradation.
Prepared
Confidence
high
Sources
5

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-2021-47075 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.3 (3.1)
Known Exploited
No
Published

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

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
4Source 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
5.3CVSS 3.1MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L3.91.4CISA-ADP

Vulnerability scoring details

Base CVSS 3.1 score

5.3Medium
CVSS 3.1 vector shape for CVE-2021-47075Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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
LinuxLinux94a39d61f80fcd679debda11e1ca02b88d90e67e, 94a39d61f80fcd679debda11e1ca02b88d90e67e, 94a39d61f80fcd679debda11e1ca02b88d90e67eunaffected
LinuxLinux5.7, 0, 5.10.40, 5.12.7, 5.13affected
Weakness

CWE details

No CWE listed

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