CVE-2021-47417

Local denial of service via strset memory leak

Published May 21, 2024 · Updated May 11, 2026

Memory leakage in Linux 5.13 through 5.14.11 allows local users to interrupt service through libbpf string-set cleanup. The strset__free() function releases the string hash and data buffer but fails to free the enclosing strset allocation. Exploitation requires local low-privileged access and repeated string-set lifecycles, exhausting memory until affected tooling or the host becomes unavailable.

CVSS severity5.5
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leakage in Linux 5.13 through 5.14.11 allows local users to interrupt service through libbpf string-set cleanup. The strset__free() function releases the string hash and data buffer but fails to free the enclosing strset allocation. Exploitation requires local low-privileged access and repeated string-set lifecycles, exhausting memory until affected tooling or the host becomes unavailable.

The record

CVE
CVE-2021-47417
Published
May 21, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499.003
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 21, 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=5.13
  2. Affected versionversion=90d76d3ececc74bf43b2a97f178dadfa1e52be54 <9e8e7504e09831c469b67d6dc11d9a72654bdb8c
  3. Affected versionversion=90d76d3ececc74bf43b2a97f178dadfa1e52be54 <b0e875bac0fab3e7a7431c2eee36a8ccc0c712ac

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.13; version=90d76d3ececc74bf43b2a97f178dadfa1e52be54 <9e8e7504e09831c469b67d6dc11d9a72654bdb8c; version=90d76d3ececc74bf43b2a97f178dadfa1e52be54 <b0e875bac0fab3e7a7431c2eee36a8ccc0c712ac

Published CVSS scores

5.5NVDCVSS: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
T1499.003Application Exhaustion Flood

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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