CVE-2021-47368

Kernel disclosure and crash via stale affinity hint

Published May 21, 2024 · Updated Aug 5, 2026

Use-after-free in the Linux kernel ENETC driver allows local users to disclose kernel memory or crash the system through procfs. enetc_setup_irqs passes a stack-backed cpumask to irq_set_affinity_hint, which retains the pointer after the function returns; irq_affinity_hint_proc_show later dereferences that stale address. Exploitation requires an active ENETC interface and a read of its world-readable /proc/irq//affinity_hint entry, exposing reused kernel-stack contents or causing a paging-request oops.

CVSS severity7.1
High
EPSS probability0.64%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Use-after-free in the Linux kernel ENETC driver allows local users to disclose kernel memory or crash the system through procfs. enetc_setup_irqs passes a stack-backed cpumask to irq_set_affinity_hint, which retains the pointer after the function returns; irq_affinity_hint_proc_show later dereferences that stale address. Exploitation requires an active ENETC interface and a read of its world-readable /proc/irq//affinity_hint entry, exposing reused kernel-stack contents or causing a paging-request oops.

The record

CVE
CVE-2021-47368
Published
May 21, 2024
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-400
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 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=5.1
  2. Affected versionversion=d4fd0404c1c95b17880f254ebfee3485693fa8ba <4c4c3052911b577920353a7646e4883d5da40c28
  3. Affected versionversion=d4fd0404c1c95b17880f254ebfee3485693fa8ba <6c3f1b741c6c2914ea120e3a5790d3e900152f7b
  4. Affected versionversion=d4fd0404c1c95b17880f254ebfee3485693fa8ba <6f329d9da2a5ae032fcde800a99b118124ed5270
  5. Affected versionversion=d4fd0404c1c95b17880f254ebfee3485693fa8ba <7237a494decfa17d0b9d0076e6cee3235719de90

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.1; version=d4fd0404c1c95b17880f254ebfee3485693fa8ba <4c4c3052911b577920353a7646e4883d5da40c28; version=d4fd0404c1c95b17880f254ebfee3485693fa8ba <6c3f1b741c6c2914ea120e3a5790d3e900152f7b; version=d4fd0404c1c95b17880f254ebfee3485693fa8ba <6f329d9da2a5ae032fcde800a99b118124ed5270; version=d4fd0404c1c95b17880f254ebfee3485693fa8ba <7237a494decfa17d0b9d0076e6cee3235719de90
The Linux Kernel Organization · Linux Kernelversion=5.1; version=d4fd0404c1c9 <4c4c3052911b; version=d4fd0404c1c9 <6c3f1b741c6c; version=d4fd0404c1c9 <6f329d9da2a5; version=d4fd0404c1c9 <7237a494decf

Published CVSS scores

7.1Linux kernel CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
8.1CISA ADP VulnrichmentCVSS:3.1/AV:N/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.

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

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption

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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo