CVE-2025-39920

Kernel crash via unchecked interval allocation failure

Published Oct 1, 2025 · Updated May 11, 2026

NULL-pointer dereference in Linux kernel PCMCIA memory validation allows local users to crash the system during allocation failure. do_validate_mem() ignores an add_interval() allocation error, allowing a null pointer to enter its interval list before sub_interval() dereferences it. Reachability requires local low-privileged access, the PCMCIA memory-validation path, and a failed kmalloc(); the bounded consequence is a kernel crash.

CVSS severity5.5
Medium
EPSS probability0.16%
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 Linux kernel PCMCIA memory validation allows local users to crash the system during allocation failure. do_validate_mem() ignores an add_interval() allocation error, allowing a null pointer to enter its interval list before sub_interval() dereferences it. Reachability requires local low-privileged access, the PCMCIA memory-validation path, and a failed kmalloc(); the bounded consequence is a kernel crash.

The record

CVE
CVE-2025-39920
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=2.6.34
  2. Affected versionversion=7b4884ca8853a638df0eb5d251d80d67777b8b1a <06b26e3099207c94b3d1be8565aedc6edc4f0a60
  3. Affected versionversion=7b4884ca8853a638df0eb5d251d80d67777b8b1a <289b58f8ff3198d091074a751d6b8f6827726f3e
  4. Affected versionversion=7b4884ca8853a638df0eb5d251d80d67777b8b1a <369bf6e241506583f4ee7593c53b92e5a9f271b4
  5. Affected versionversion=7b4884ca8853a638df0eb5d251d80d67777b8b1a <4a81f78caa53e0633cf311ca1526377d9bff7479
  6. Affected versionversion=7b4884ca8853a638df0eb5d251d80d67777b8b1a <5b60ed401b47897352c520bc724c85aa908dedcc
  7. Affected versionversion=7b4884ca8853a638df0eb5d251d80d67777b8b1a <85be7ef8c8e792a414940a38d94565dd48d2f236
  8. Affected versionversion=7b4884ca8853a638df0eb5d251d80d67777b8b1a <8699358b6ac99b8ccc97ed9e6e3669ef8958ef7b
  9. Affected versionversion=7b4884ca8853a638df0eb5d251d80d67777b8b1a <ae184024ef31423e5beb44cf4f52999bbcf2fe5b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.34; version=7b4884ca8853a638df0eb5d251d80d67777b8b1a <06b26e3099207c94b3d1be8565aedc6edc4f0a60; version=7b4884ca8853a638df0eb5d251d80d67777b8b1a <289b58f8ff3198d091074a751d6b8f6827726f3e; version=7b4884ca8853a638df0eb5d251d80d67777b8b1a <369bf6e241506583f4ee7593c53b92e5a9f271b4; version=7b4884ca8853a638df0eb5d251d80d67777b8b1a <4a81f78caa53e0633cf311ca1526377d9bff7479; version=7b4884ca8853a638df0eb5d251d80d67777b8b1a <5b60ed401b47897352c520bc724c85aa908dedcc; version=7b4884ca8853a638df0eb5d251d80d67777b8b1a <85be7ef8c8e792a414940a38d94565dd48d2f236; version=7b4884ca8853a638df0eb5d251d80d67777b8b1a <8699358b6ac99b8ccc97ed9e6e3669ef8958ef7b; version=7b4884ca8853a638df0eb5d251d80d67777b8b1a <ae184024ef31423e5beb44cf4f52999bbcf2fe5b

Published CVSS scores

5.5NVDCVSS: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 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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