CVE-2025-38023

Kernel crash via invalid NFS unlock context

Published Jun 18, 2025 · Updated May 11, 2026

NULL pointer dereference in the Linux kernel NFS client allows local users to crash the kernel during low-memory NFSv4 unlock handling. When nfs_get_lock_context returns -ENOMEM, the unlock path retains the error-valued l_ctx in nfs4_unlockdata and passes it to rpc_run_task, which dereferences a null context in nfs4_locku_prepare. Exploitation requires low-privilege local access, an NFSv4 unlock operation, and allocation failure under memory pressure; the bounded consequence is a kernel crash.

CVSS severity5.5
Medium
EPSS probability0.19%
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 NFS client allows local users to crash the kernel during low-memory NFSv4 unlock handling. When nfs_get_lock_context returns -ENOMEM, the unlock path retains the error-valued l_ctx in nfs4_unlockdata and passes it to rpc_run_task, which dereferences a null context in nfs4_locku_prepare. Exploitation requires low-privilege local access, an NFSv4 unlock operation, and allocation failure under memory pressure; the bounded consequence is a kernel crash.

The record

CVE
CVE-2025-38023
Published
Jun 18, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 18, 2025CVE 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=4.12
  2. Affected versionversion=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <4c189fd40a09a03f9a900bedb2d9064f1734d72a
  3. Affected versionversion=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <72f552e00c50f265896d3c19edc6696aa2910081
  4. Affected versionversion=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <85fb7f8ca5f8c138579fdfc9b97b3083e6077d40
  5. Affected versionversion=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <a6879a076b98c99c9fe747816fe1c29543442441
  6. Affected versionversion=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <c457dc1ec770a22636b473ce5d35614adfe97636
  7. Affected versionversion=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <da824f1271633bcb515ca8084cda3eda4b3ace51
  8. Affected versionversion=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <db6f5ee1fc8f54d079d0751292c2fc2d78e3aad1
  9. Affected versionversion=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <f601960af04d2ecb007c928ba153d34051acd9c1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.12; version=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <4c189fd40a09a03f9a900bedb2d9064f1734d72a; version=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <72f552e00c50f265896d3c19edc6696aa2910081; version=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <85fb7f8ca5f8c138579fdfc9b97b3083e6077d40; version=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <a6879a076b98c99c9fe747816fe1c29543442441; version=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <c457dc1ec770a22636b473ce5d35614adfe97636; version=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <da824f1271633bcb515ca8084cda3eda4b3ace51; version=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <db6f5ee1fc8f54d079d0751292c2fc2d78e3aad1; version=f30cb757f680f965ba8a2e53cb3588052a01aeb5 <f601960af04d2ecb007c928ba153d34051acd9c1

Published CVSS scores

5.5CanonicalCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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