CVE-2021-47572

Service interruption via invalid IPv6 nexthop cleanup

Published May 24, 2024 · Updated May 11, 2026

NULL pointer dereference in the Linux kernel allows local users to trigger a kernel oops by submitting an IPv6 nexthop request. In nh_create_ipv6(), the error path calls the absent ipv6_stub->fib6_nh_release hook after fib6_nh_init returns -EAFNOSUPPORT, transferring control through a NULL pointer. The trigger requires an affected kernel built without CONFIG_IPV6 and permission to add a nexthop through rtnetlink; a resulting panic can interrupt service.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
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 the Linux kernel allows local users to trigger a kernel oops by submitting an IPv6 nexthop request. In nh_create_ipv6(), the error path calls the absent ipv6_stub->fib6_nh_release hook after fib6_nh_init returns -EAFNOSUPPORT, transferring control through a NULL pointer. The trigger requires an affected kernel built without CONFIG_IPV6 and permission to add a nexthop through rtnetlink; a resulting panic can interrupt service.

The record

CVE
CVE-2021-47572
Published
May 24, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. May 24, 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

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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=5.3
  2. Affected versionversion=53010f991a9f5e4ed2db705ddde6ff32709192a2 <1c743127cc54b112b155f434756bd4b5fa565a99
  3. Affected versionversion=53010f991a9f5e4ed2db705ddde6ff32709192a2 <39509d76a9a3d02f379d52cb4b1449469c56c0e0
  4. Affected versionversion=53010f991a9f5e4ed2db705ddde6ff32709192a2 <7b6f44856da5ba0b1aa61403eb9fddd272156503
  5. Affected versionversion=53010f991a9f5e4ed2db705ddde6ff32709192a2 <b70ff391deeec35cdd8a05f5f63f5fe28bc4f225

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.3; version=53010f991a9f5e4ed2db705ddde6ff32709192a2 <1c743127cc54b112b155f434756bd4b5fa565a99; version=53010f991a9f5e4ed2db705ddde6ff32709192a2 <39509d76a9a3d02f379d52cb4b1449469c56c0e0; version=53010f991a9f5e4ed2db705ddde6ff32709192a2 <7b6f44856da5ba0b1aa61403eb9fddd272156503; version=53010f991a9f5e4ed2db705ddde6ff32709192a2 <b70ff391deeec35cdd8a05f5f63f5fe28bc4f225

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

CWE-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application 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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