CVE-2021-46983Network attack vector

Remote kernel crash via invalid CQ context

Published Feb 28, 2024 · Updated Aug 5, 2026

NULL pointer dereference in nvmet-rdma in affected Linux kernel releases allows remote attackers to crash an NVMe-oF RDMA target. The nvmet_rdma_error_comp function reads the obsolete cq_context after a shared-CQ SEND fails instead of obtaining the queue from wc->qp. An enabled nvmet-rdma port and peer-induced retry-exceeded completion are required; the resulting kernel oops can panic the target host.

CVSS severity7.5
High
EPSS probability0.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in nvmet-rdma in affected Linux kernel releases allows remote attackers to crash an NVMe-oF RDMA target. The nvmet_rdma_error_comp function reads the obsolete cq_context after a shared-CQ SEND fails instead of obtaining the queue from wc->qp. An enabled nvmet-rdma port and peer-induced retry-exceeded completion are required; the resulting kernel oops can panic the target host.

The record

CVE
CVE-2021-46983
Published
Feb 28, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 28, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=5.9
  2. Affected versionversion=ca0f1a8055be2a04073af435dc68419334481638 <17fb6dfa5162b89ecfa07df891a53afec321abe8
  3. Affected versionversion=ca0f1a8055be2a04073af435dc68419334481638 <5bdb34466ad8370546dfa0497594fb1d6f2fed90
  4. Affected versionversion=ca0f1a8055be2a04073af435dc68419334481638 <64f3410c7bfc389b1a58611d0799f4a36ce4b6b5
  5. Affected versionversion=ca0f1a8055be2a04073af435dc68419334481638 <8cc365f9559b86802afc0208389f5c8d46b4ad61

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.9; version=ca0f1a8055be2a04073af435dc68419334481638 <17fb6dfa5162b89ecfa07df891a53afec321abe8; version=ca0f1a8055be2a04073af435dc68419334481638 <5bdb34466ad8370546dfa0497594fb1d6f2fed90; version=ca0f1a8055be2a04073af435dc68419334481638 <64f3410c7bfc389b1a58611d0799f4a36ce4b6b5; version=ca0f1a8055be2a04073af435dc68419334481638 <8cc365f9559b86802afc0208389f5c8d46b4ad61

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5Linux kernel CVE teamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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-476NULL Pointer Dereference
T1499.004Application or System Exploitation

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

See the directory against your own environment.

Your stack

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