CVE-2025-39895

Boot-time crash via offline CPU mask dereference

Published Oct 1, 2025 · Updated May 11, 2026

NULL pointer dereference in affected Linux kernel releases allows local users to trigger a kernel panic during boot. sched_numa_find_nth_cpu() dereferences a failed binary-search result when its NUMA masks do not intersect the requested CPU set. Reachability requires every CPU in that set to be offline; the resulting kernel oops kills init and panics the system.

CVSS severity5.5
Medium
EPSS probability0.15%
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 affected Linux kernel releases allows local users to trigger a kernel panic during boot. sched_numa_find_nth_cpu() dereferences a failed binary-search result when its NUMA masks do not intersect the requested CPU set. Reachability requires every CPU in that set to be offline; the resulting kernel oops kills init and panics the system.

The record

CVE
CVE-2025-39895
Published
Oct 1, 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. Oct 1, 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=6.3
  2. Affected versionversion=cd7f55359c90a4108e6528e326b8623fce1ad72a <5ebf512f335053a42482ebff91e46c6dc156bf8c
  3. Affected versionversion=cd7f55359c90a4108e6528e326b8623fce1ad72a <b3ec50cc5eb5ca84256ca701d28b137a6036c412
  4. Affected versionversion=cd7f55359c90a4108e6528e326b8623fce1ad72a <b921c288cd8abef9af5b59e056a63cc2c263a9e3
  5. Affected versionversion=cd7f55359c90a4108e6528e326b8623fce1ad72a <f9b8d4dba8e78c1887fecd81ba0d8204d6ff05fc

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.3; version=cd7f55359c90a4108e6528e326b8623fce1ad72a <5ebf512f335053a42482ebff91e46c6dc156bf8c; version=cd7f55359c90a4108e6528e326b8623fce1ad72a <b3ec50cc5eb5ca84256ca701d28b137a6036c412; version=cd7f55359c90a4108e6528e326b8623fce1ad72a <b921c288cd8abef9af5b59e056a63cc2c263a9e3; version=cd7f55359c90a4108e6528e326b8623fce1ad72a <f9b8d4dba8e78c1887fecd81ba0d8204d6ff05fc

Published CVSS scores

5.5CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5NIST NVDCVSS: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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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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