CVE-2026-53392Network attack vector

Client panic via zero-count flexfiles layout

Published Jul 19, 2026 · Updated Jul 19, 2026

NULL-pointer dereference in the Linux Kernel allows remote attackers to panic NFSv4 flexfiles clients via a crafted layout. ff_layout_alloc_lseg() accepts a zero filehandle-version count, stores the resulting ZERO_SIZE_PTR, and later code dereferences fh_versions[0]. Exploitation requires an established pNFS flexfiles mount and control or impersonation of its NFS server; the resulting fatal exception interrupts the client host.

CVSS severity7.5
High
EPSS probability0.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL-pointer dereference in the Linux Kernel allows remote attackers to panic NFSv4 flexfiles clients via a crafted layout. ff_layout_alloc_lseg() accepts a zero filehandle-version count, stores the resulting ZERO_SIZE_PTR, and later code dereferences fh_versions[0]. Exploitation requires an established pNFS flexfiles mount and control or impersonation of its NFS server; the resulting fatal exception interrupts the client host.

The record

CVE
CVE-2026-53392
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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=4.0
  2. Affected versionversion=d67ae825a59d639e4d8b82413af84d854617a87e <2131ed64b767ffa8bcdb3677d90f3964e39aabc8
  3. Affected versionversion=d67ae825a59d639e4d8b82413af84d854617a87e <2c6bb3c40bc24f6aa8dfbe6fe98c3ad6389203f2
  4. Affected versionversion=d67ae825a59d639e4d8b82413af84d854617a87e <7779c85028a0676fb190cde4f0c540f4f8e97761
  5. Affected versionversion=d67ae825a59d639e4d8b82413af84d854617a87e <d8c90c7cc061265d5f2813a1f5c82ef2f4707e67

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.0; version=d67ae825a59d639e4d8b82413af84d854617a87e <2131ed64b767ffa8bcdb3677d90f3964e39aabc8; version=d67ae825a59d639e4d8b82413af84d854617a87e <2c6bb3c40bc24f6aa8dfbe6fe98c3ad6389203f2; version=d67ae825a59d639e4d8b82413af84d854617a87e <7779c85028a0676fb190cde4f0c540f4f8e97761; version=d67ae825a59d639e4d8b82413af84d854617a87e <d8c90c7cc061265d5f2813a1f5c82ef2f4707e67

Published CVSS scores

7.5kernel.orgCVSS: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

CWE-476NULL Pointer Dereference
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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