CVE-2021-47075Network attack vector

Service interruption via leaked controller queue memory

Published Mar 1, 2024 · Updated May 11, 2026

Memory leak in nvmet controller allocation in Linux allows remote attackers to interrupt service through repeated failed connections. When nvmet_alloc_ctrl detects a subsystem controller-ID minimum above its maximum, its error path skips freeing ctrl->sqs after allocating it. Reaching the leak requires a network-accessible NVMe target with the inconsistent controller-ID range, and repeated failures consume kernel memory without exposing or modifying data.

CVSS severity5.3
Medium
EPSS probability0.91%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in nvmet controller allocation in Linux allows remote attackers to interrupt service through repeated failed connections. When nvmet_alloc_ctrl detects a subsystem controller-ID minimum above its maximum, its error path skips freeing ctrl->sqs after allocating it. Reaching the leak requires a network-accessible NVMe target with the inconsistent controller-ID range, and repeated failures consume kernel memory without exposing or modifying data.

The record

CVE
CVE-2021-47075
Published
Mar 1, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 1, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=5.7
  2. Affected versionversion=94a39d61f80fcd679debda11e1ca02b88d90e67e <4720f29acb3fe67aa8aa71e6b675b079d193aaeb
  3. Affected versionversion=94a39d61f80fcd679debda11e1ca02b88d90e67e <afb680ed7ecbb7fd66ddb43650e9b533fd8b4b9a
  4. Affected versionversion=94a39d61f80fcd679debda11e1ca02b88d90e67e <fec356a61aa3d3a66416b4321f1279e09e0f256f

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.7; version=94a39d61f80fcd679debda11e1ca02b88d90e67e <4720f29acb3fe67aa8aa71e6b675b079d193aaeb; version=94a39d61f80fcd679debda11e1ca02b88d90e67e <afb680ed7ecbb7fd66ddb43650e9b533fd8b4b9a; version=94a39d61f80fcd679debda11e1ca02b88d90e67e <fec356a61aa3d3a66416b4321f1279e09e0f256f

Published CVSS scores

5.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
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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