CVE-2021-47624

Local kernel resource leak via malformed SUNRPC state

Published Jul 16, 2024 · Updated May 11, 2026

A reference-count leak in Linux kernel 5.14 allows local users to retain SUNRPC transport objects through malformed sysfs writes. The rpc_sysfs_xprt_state_change function returns EINVAL for values other than offline, online, or remove without releasing rpc_xprt and rpc_xprt_switch references acquired by its helper calls. The gate is local low-privileged access; repeated invalid writes leak unused kernel objects instead of changing transport state.

CVSS severity7.1
High
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

A reference-count leak in Linux kernel 5.14 allows local users to retain SUNRPC transport objects through malformed sysfs writes. The rpc_sysfs_xprt_state_change function returns EINVAL for values other than offline, online, or remove without releasing rpc_xprt and rpc_xprt_switch references acquired by its helper calls. The gate is local low-privileged access; repeated invalid writes leak unused kernel objects instead of changing transport state.

The record

CVE
CVE-2021-47624
Published
Jul 16, 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. Jul 16, 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=5.14
  2. Affected versionversion=5b7eb78486cd9ac58bfbd6d84ea0fe2d9fead03b <4b22aa42bd4d2d630ef1854c139275c3532937cb
  3. Affected versionversion=5b7eb78486cd9ac58bfbd6d84ea0fe2d9fead03b <5f6024c05a2c0fdd180b29395aaf686d25af3a0f
  4. Affected versionversion=5b7eb78486cd9ac58bfbd6d84ea0fe2d9fead03b <776d794f28c95051bc70405a7b1fa40115658a18

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.14; version=5b7eb78486cd9ac58bfbd6d84ea0fe2d9fead03b <4b22aa42bd4d2d630ef1854c139275c3532937cb; version=5b7eb78486cd9ac58bfbd6d84ea0fe2d9fead03b <5f6024c05a2c0fdd180b29395aaf686d25af3a0f; version=5b7eb78486cd9ac58bfbd6d84ea0fe2d9fead03b <776d794f28c95051bc70405a7b1fa40115658a18

Published CVSS scores

7.1NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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.

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Technologies

Your stack

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Your stack

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