CVE-2023-53381Network attack vector

Remote resource exhaustion via leaked mount references

Published Sep 18, 2025 · Updated Sep 18, 2025

Denial of service in Linux NFSD allows remote attackers to exhaust kernel resources via crafted NFSv4.2 COPY requests. In nfsd4_copy, an error after setup increments nsui_refcnt but omits the matching put operation, so the laundromat skips pinned source vfsmounts. An export-permitted NFS client can repeat failed asynchronous inter-server COPY operations until mounts and memory are exhausted, interrupting the server.

CVSS severity7.5
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux NFSD allows remote attackers to exhaust kernel resources via crafted NFSv4.2 COPY requests. In nfsd4_copy, an error after setup increments nsui_refcnt but omits the matching put operation, so the laundromat skips pinned source vfsmounts. An export-permitted NFS client can repeat failed asynchronous inter-server COPY operations until mounts and memory are exhausted, interrupting the server.

The record

CVE
CVE-2023-53381
Published
Sep 18, 2025
Updated
Sep 18, 2025
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.002
Attack vector
network
Privileges
unauthenticated

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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=5.14
  2. Affected versionversion=a4bc287943f5695209ff36bdc89f17b48d68fae7 <2da50149981d05955e51c28e982e9ac29bd73417
  3. Affected versionversion=f4e44b393389c77958f7c58bf4415032b4cda15b <34e8f9ec4c9ac235f917747b23a200a5e0ec857b
  4. Affected versionversion=f4e44b393389c77958f7c58bf4415032b4cda15b <6c3c05402547aaca3edb23327b50f01a881831b9
  5. Affected versionversion=f4e44b393389c77958f7c58bf4415032b4cda15b <80a15dc4a0214b55ca42675bb0bb2a8d857eb1d0
  6. Affected versionversion=f4e44b393389c77958f7c58bf4415032b4cda15b <9f0df37520a27ad99eaacf38418b3d2bb5023105

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.14; version=a4bc287943f5695209ff36bdc89f17b48d68fae7 <2da50149981d05955e51c28e982e9ac29bd73417; version=f4e44b393389c77958f7c58bf4415032b4cda15b <34e8f9ec4c9ac235f917747b23a200a5e0ec857b; version=f4e44b393389c77958f7c58bf4415032b4cda15b <6c3c05402547aaca3edb23327b50f01a881831b9; version=f4e44b393389c77958f7c58bf4415032b4cda15b <80a15dc4a0214b55ca42675bb0bb2a8d857eb1d0; version=f4e44b393389c77958f7c58bf4415032b4cda15b <9f0df37520a27ad99eaacf38418b3d2bb5023105

Published CVSS scores

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.5LinuxCVSS:3.1/AV:N/AC:L/PR:N/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.002Service 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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