CVE-2021-3669

Local denial of service via costly IPC scan

Published Aug 26, 2022 · Updated Nov 3, 2025

Uncontrolled resource consumption in the Linux kernel allows local users to cause a denial of service through large shared-memory counts. The sysvipc_find_ipc() iterator in ipc/util.c repeatedly scans the IPC ID table while serving /proc/sysvipc/shm instead of checking its stored maximum index. Exploitation requires low-privileged local access and a shared-memory-segment count normally above configured limits, with resource exhaustion as the bounded impact.

CVSS severity5.5
Medium
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled resource consumption in the Linux kernel allows local users to cause a denial of service through large shared-memory counts. The sysvipc_find_ipc() iterator in ipc/util.c repeatedly scans the IPC ID table while serving /proc/sysvipc/shm instead of checking its stored maximum index. Exploitation requires low-privileged local access and a shared-memory-segment count normally above configured limits, with resource exhaustion as the bounded impact.

The record

CVE
CVE-2021-3669
Published
Aug 26, 2022
Updated
Nov 3, 2025
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-400, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 26, 2022CVE publishedPublication date reported by the CVE source.
  2. Nov 3, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=Not Known

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=Not Known

Published CVSS scores

5.5Oracle LinuxCVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.

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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

CWE-400Uncontrolled Resource Consumption
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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