CVE-2021-47076

Host crash via stale failed WQE status

Published Mar 1, 2024 · Updated May 11, 2026

Denial of service in the Linux kernel allows local users to crash the host through a crafted Soft-RoCE atomic operation. The rxe_completer path leaves the work queue element status unchanged after a LOCAL_WRITE key-validation failure, then reaches a warning that panics the kernel instead of returning a completion error. Reachability requires low-privileged local access and an active rdma_rxe path; the documented consequence is a host crash without data disclosure or modification.

CVSS severity5.5
Medium
EPSS probability0.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel allows local users to crash the host through a crafted Soft-RoCE atomic operation. The rxe_completer path leaves the work queue element status unchanged after a LOCAL_WRITE key-validation failure, then reaches a warning that panics the kernel instead of returning a completion error. Reachability requires low-privileged local access and an active rdma_rxe path; the documented consequence is a host crash without data disclosure or modification.

The record

CVE
CVE-2021-47076
Published
Mar 1, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

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=4.8
  2. Affected versionversion=8700e3e7c4857d28ebaa824509934556da0b3e76 <a81e72d49b0648f68ab201163dbfc7841056d7a2
  3. Affected versionversion=8700e3e7c4857d28ebaa824509934556da0b3e76 <abe31d25facdb9109fe2cf69890748295291570c
  4. Affected versionversion=8700e3e7c4857d28ebaa824509934556da0b3e76 <dc07628bd2bbc1da768e265192c28ebd301f509d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.8; version=8700e3e7c4857d28ebaa824509934556da0b3e76 <a81e72d49b0648f68ab201163dbfc7841056d7a2; version=8700e3e7c4857d28ebaa824509934556da0b3e76 <abe31d25facdb9109fe2cf69890748295291570c; version=8700e3e7c4857d28ebaa824509934556da0b3e76 <dc07628bd2bbc1da768e265192c28ebd301f509d

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:L/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

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

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Your stack

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