CVE-2026-53399Network attack vector

Kernel memory corruption via freed layout stateid

Published Jul 19, 2026 · Updated Jul 19, 2026

Use-after-free in Linux Kernel nfsd allows remote attackers to read or corrupt kernel memory via crafted NFSv4 LAYOUTGET requests. On setlease failure, nfsd4_alloc_layout_stateid() frees an IDR-published stateid without removing its slot, so later IDR walkers dereference freed slab memory. An NFSv4 client must reach a pNFS block or SCSI export; successful triggering can corrupt kernel state, panic the kernel, or hang the server.

CVSS severity9.8
Critical
EPSS probability0.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux Kernel nfsd allows remote attackers to read or corrupt kernel memory via crafted NFSv4 LAYOUTGET requests. On setlease failure, nfsd4_alloc_layout_stateid() frees an IDR-published stateid without removing its slot, so later IDR walkers dereference freed slab memory. An NFSv4 client must reach a pNFS block or SCSI export; successful triggering can corrupt kernel state, panic the kernel, or hang the server.

The record

CVE
CVE-2026-53399
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
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=c5c707f96fc9a6e5a57ca5baac892673270abe3d <30d55c8aabb261bc3f427d6b9aae7ef6206063f9
  3. Affected versionversion=c5c707f96fc9a6e5a57ca5baac892673270abe3d <83c2b7797742339bb768f83935f7ca33950db138
  4. Affected versionversion=c5c707f96fc9a6e5a57ca5baac892673270abe3d <8dee7c278f1c2b5bb80e17a6281c3812fc8b0cdd
  5. Affected versionversion=c5c707f96fc9a6e5a57ca5baac892673270abe3d <d369e5edfaaf83a448016e2f1da392b2174be801

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.0; version=c5c707f96fc9a6e5a57ca5baac892673270abe3d <30d55c8aabb261bc3f427d6b9aae7ef6206063f9; version=c5c707f96fc9a6e5a57ca5baac892673270abe3d <83c2b7797742339bb768f83935f7ca33950db138; version=c5c707f96fc9a6e5a57ca5baac892673270abe3d <8dee7c278f1c2b5bb80e17a6281c3812fc8b0cdd; version=c5c707f96fc9a6e5a57ca5baac892673270abe3d <d369e5edfaaf83a448016e2f1da392b2174be801

Published CVSS scores

9.8Linux kernel CVE teamCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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

T1499.004Application 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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