CVE-2021-47536Network attack vector

Kernel memory corruption via wrong link-group deletion

Published May 24, 2024 · Updated Aug 5, 2026

Memory corruption in Linux kernel 5.5 through 5.10.83, 5.11 through 5.15.6, and 5.16 release candidates allows remote attackers to crash the kernel. smc_lgr_cleanup_early deletes the link-group list head instead of the actual group, then clears the still-linked group and leaves corrupted list pointers. An unauthenticated peer must reach an active SMC listener and disrupt its CLC handshake; subsequent list processing can panic the host or corrupt kernel memory.

CVSS severity9.8
Critical
EPSS probability0.59%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory corruption in Linux kernel 5.5 through 5.10.83, 5.11 through 5.15.6, and 5.16 release candidates allows remote attackers to crash the kernel. smc_lgr_cleanup_early deletes the link-group list head instead of the actual group, then clears the still-linked group and leaves corrupted list pointers. An unauthenticated peer must reach an active SMC listener and disrupt its CLC handshake; subsequent list processing can panic the host or corrupt kernel memory.

The record

CVE
CVE-2021-47536
Published
May 24, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-787, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 24, 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

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=5.5
  2. Affected versionversion=a0a62ee15a829ebf8aeec55a4f1688230439b3e0 <77731fede297a23d26f2d169b4269466b2c82529
  3. Affected versionversion=a0a62ee15a829ebf8aeec55a4f1688230439b3e0 <789b6cc2a5f9123b9c549b886fdc47c865cfe0ba
  4. Affected versionversion=a0a62ee15a829ebf8aeec55a4f1688230439b3e0 <95518fe354d712dca6f431cf2a11b8f63bc9a66c

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.5; version=a0a62ee15a829ebf8aeec55a4f1688230439b3e0 <77731fede297a23d26f2d169b4269466b2c82529; version=a0a62ee15a829ebf8aeec55a4f1688230439b3e0 <789b6cc2a5f9123b9c549b886fdc47c865cfe0ba; version=a0a62ee15a829ebf8aeec55a4f1688230439b3e0 <95518fe354d712dca6f431cf2a11b8f63bc9a66c

Published CVSS scores

9.8Linux kernel CVE teamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS: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.

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1190Exploit Public-Facing Application

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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