CVE-2021-47529

Kernel memory exhaustion via leaked reduce-power buffers

Published May 24, 2024 · Updated May 11, 2026

Memory leak in the iwlwifi UEFI parser in Linux 5.14 through 5.15.6 allows local users to exhaust kernel memory via malformed TLVs. The reduce-power parser returns on an invalid TLV length or allocation failure without freeing the buffer already accumulated in reduce_power_data. Reachability requires the iwlwifi driver to process malformed reduce-power data from UEFI; repeated error-path activation exhausts kernel memory and interrupts system operation.

CVSS severity5.5
Medium
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

Memory leak in the iwlwifi UEFI parser in Linux 5.14 through 5.15.6 allows local users to exhaust kernel memory via malformed TLVs. The reduce-power parser returns on an invalid TLV length or allocation failure without freeing the buffer already accumulated in reduce_power_data. Reachability requires the iwlwifi driver to process malformed reduce-power data from UEFI; repeated error-path activation exhausts kernel memory and interrupts system operation.

The record

CVE
CVE-2021-47529
Published
May 24, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499.004
Attack vector
local
Privileges
authenticated

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=5.14
  2. Affected versionversion=9dad325f9d57508b154f0bebbc341a8528e5729c <4768935c25403ba96e7a745645df24a51a774b7e
  3. Affected versionversion=9dad325f9d57508b154f0bebbc341a8528e5729c <a571bc28326d9f3e13f5f2d9cda2883e0631b0ce

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.14; version=9dad325f9d57508b154f0bebbc341a8528e5729c <4768935c25403ba96e7a745645df24a51a774b7e; version=9dad325f9d57508b154f0bebbc341a8528e5729c <a571bc28326d9f3e13f5f2d9cda2883e0631b0ce

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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 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

CWE-401Missing Release of Memory after Effective Lifetime
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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