CVE-2023-53403

Local denial of service via leaked dentries

Published Sep 18, 2025 · Updated Sep 18, 2025

Missing memory release in the Linux kernel allows local users to exhaust kernel memory through the time debug test interface. In kernel/time/test_udelay.c, cleanup calls debugfs_lookup() without releasing the returned dentry, so each affected lookup retains memory beyond its lifetime. Triggering the vulnerable cleanup path requires local low-privilege access; repeated invocations consume memory until system availability is degraded.

CVSS severity5.5
Medium
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing memory release in the Linux kernel allows local users to exhaust kernel memory through the time debug test interface. In kernel/time/test_udelay.c, cleanup calls debugfs_lookup() without releasing the returned dentry, so each affected lookup retains memory beyond its lifetime. Triggering the vulnerable cleanup path requires local low-privilege access; repeated invocations consume memory until system availability is degraded.

The record

CVE
CVE-2023-53403
Published
Sep 18, 2025
Updated
Sep 18, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-401, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 18, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <15cffd01ed80e3506e29ba9f441e2358413b7317
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5b268d8abaec6cbd4bd70d062e769098d96670aa
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b588b42d077ce93c98704b41003bcec6a564b738
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dc39fbd865a9819db4b622f610ba17b2ebc294f4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <15cffd01ed80e3506e29ba9f441e2358413b7317; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5b268d8abaec6cbd4bd70d062e769098d96670aa; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b588b42d077ce93c98704b41003bcec6a564b738; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dc39fbd865a9819db4b622f610ba17b2ebc294f4

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5CISA-ADPCVSS: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-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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