CVE-2021-46937

Kernel memory leak via repeated DAMON target writes

Published Feb 27, 2024 · Updated May 11, 2026

Memory leak in Linux kernel 5.15 through 5.15.12 allows local users to retain kernel PID objects via repeated DAMON target writes. The dbgfs_target_ids_write() callback acquires new struct pid references but does not release the previous references when target_ids is rewritten without starting and terminating monitoring. Access requires permission to write the mounted DAMON debugfs interface; repeated writes consume unreclaimable kernel memory without altering application data.

CVSS severity5.5
Medium
EPSS probability0.22%
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 Linux kernel 5.15 through 5.15.12 allows local users to retain kernel PID objects via repeated DAMON target writes. The dbgfs_target_ids_write() callback acquires new struct pid references but does not release the previous references when target_ids is rewritten without starting and terminating monitoring. Access requires permission to write the mounted DAMON debugfs interface; repeated writes consume unreclaimable kernel memory without altering application data.

The record

CVE
CVE-2021-46937
Published
Feb 27, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-668, T1499.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 27, 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=4bc05954d0076655cfaf6f0135585bdc20cd6b11 <ebb3f994dd92f8fb4d70c7541091216c1e10cb71
  2. Affected versionversion=4bc05954d0076655cfaf6f0135585bdc20cd6b11 <ffe4a1ba1a82c416a6b3a09d46594f6a885ae141
  3. Affected versionversion=5.15

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4bc05954d0076655cfaf6f0135585bdc20cd6b11 <ebb3f994dd92f8fb4d70c7541091216c1e10cb71; version=4bc05954d0076655cfaf6f0135585bdc20cd6b11 <ffe4a1ba1a82c416a6b3a09d46594f6a885ae141; version=5.15

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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-668Exposure of Resource to Wrong Sphere
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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