CVE-2021-3759

Service interruption via unaccounted IPC allocations

Published Aug 23, 2022 · Updated Aug 3, 2024

Uncontrolled resource consumption in Linux kernel releases before 5.15-rc1 allows local users to exhaust host memory through semaphore creation. IPC semaphore objects and undo lists allocated through semget are not charged to the caller's memory cgroup, so repeated creation bypasses memcg limits. A low-privileged user inside a memcg-limited container can deplete host memory and interrupt service.

CVSS severity5.5
Medium
EPSS probability0.36%
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 Linux kernel releases before 5.15-rc1 allows local users to exhaust host memory through semaphore creation. IPC semaphore objects and undo lists allocated through semget are not charged to the caller's memory cgroup, so repeated creation bypasses memcg limits. A low-privileged user inside a memcg-limited container can deplete host memory and interrupt service.

The record

CVE
CVE-2021-3759
Published
Aug 23, 2022
Updated
Aug 3, 2024
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-770, CWE-400, T1499.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 23, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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=Fixed in Linux kernel 5.15-rc1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=Fixed in Linux kernel 5.15-rc1

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.

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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-770Allocation of Resources Without Limits or Throttling
CWE-400Uncontrolled Resource Consumption
T1499.001OS 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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