CVE-2021-47616

Kernel memory corruption via RDMA queue double-free

Published Jun 19, 2024 · Updated Aug 5, 2026

Use-after-free in Linux 5.15 allows local users to corrupt kernel memory by triggering an RDMA queue-pair creation failure. In rxe_qp_from_init(), the error path frees qp->sq.queue without clearing the pointer, so final cleanup frees the same queue again. Reaching the flaw requires low-privileged local access and an RDMA setup failure; public sources establish memory corruption but no reliable privilege-escalation outcome.

CVSS severity7.8
High
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux 5.15 allows local users to corrupt kernel memory by triggering an RDMA queue-pair creation failure. In rxe_qp_from_init(), the error path frees qp->sq.queue without clearing the pointer, so final cleanup frees the same queue again. Reaching the flaw requires low-privileged local access and an RDMA setup failure; public sources establish memory corruption but no reliable privilege-escalation outcome.

The record

CVE
CVE-2021-47616
Published
Jun 19, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 19, 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=514aee660df493cd673154a6ba6bab745ec47b8c <84b01721e8042cdd1e8ffeb648844a09cd4213e0
  2. Affected versionversion=514aee660df493cd673154a6ba6bab745ec47b8c <acb53e47db1fbc7cd37ab10b46388f045a76e383
  3. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=514aee660df493cd673154a6ba6bab745ec47b8c <84b01721e8042cdd1e8ffeb648844a09cd4213e0; version=514aee660df493cd673154a6ba6bab745ec47b8c <acb53e47db1fbc7cd37ab10b46388f045a76e383; version=5.15

Published CVSS scores

7.8CanonicalCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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

No sourced classifications are available.

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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