CVE-2021-47392

RDMA teardown hang via leaked listener references

Published May 21, 2024 · Updated May 23, 2026

Deadlock in the RDMA connection manager in Linux 5.10.4 through 5.10.70 and 5.11 allows local users to hang RDMA connection teardown. A failure in cma_listen_on_all() adds per-device IDs to listen_list without atomically setting the bound state or removing them on error. A local user must reach the RDMA userspace connection-manager interface and trigger the failed listen path; later ID destruction waits forever on retained references.

CVSS severityUnavailable
Unscored
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deadlock in the RDMA connection manager in Linux 5.10.4 through 5.10.70 and 5.11 allows local users to hang RDMA connection teardown. A failure in cma_listen_on_all() adds per-device IDs to listen_list without atomically setting the bound state or removing them on error. A local user must reach the RDMA userspace connection-manager interface and trigger the failed listen path; later ID destruction waits forever on retained references.

The record

CVE
CVE-2021-47392
Published
May 21, 2024
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. May 21, 2024CVE publishedPublication date reported by the CVE source.
  2. May 23, 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=5.10.4 <5.10.71
  2. Affected versionversion=5.11
  3. Affected versionversion=70ba8b1697e35c04ea5f22edb6e401aeb1208d96 <3f4e68902d2e545033c80d7ad62fd9a439e573f4
  4. Affected versionversion=c80a0c52d85c49a910d0dc0e342e8d8898677dc0 <ca465e1f1f9b38fe916a36f7d80c5d25f2337c81
  5. Affected versionversion=c80a0c52d85c49a910d0dc0e342e8d8898677dc0 <e56a5146ef8cb51cd7c9e748267dce7564448a35

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.10.4 <5.10.71; version=5.11; version=70ba8b1697e35c04ea5f22edb6e401aeb1208d96 <3f4e68902d2e545033c80d7ad62fd9a439e573f4; version=c80a0c52d85c49a910d0dc0e342e8d8898677dc0 <ca465e1f1f9b38fe916a36f7d80c5d25f2337c81; version=c80a0c52d85c49a910d0dc0e342e8d8898677dc0 <e56a5146ef8cb51cd7c9e748267dce7564448a35

Published CVSS scores

No CVSS assessment is available in this record.

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
PrivilegesUnavailable
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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