CVE-2026-23439

Kernel crash via false-success IPv6 socket creation

Published Apr 3, 2026 · Updated Apr 3, 2026

NULL pointer dereference in affected Linux Kernel releases allows local users to crash the kernel through a privileged FOU Netlink request. When IPv6 support is disabled, udp_sock_create6 returns success without initializing the socket pointer, and fou_create dereferences it. Reaching the FOU generic-Netlink path requires a privileged local user; the resulting NULL dereference interrupts the system.

CVSS severity5.5
Medium
EPSS probability0.13%
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 crash the kernel through a privileged FOU Netlink request. When IPv6 support is disabled, udp_sock_create6 returns success without initializing the socket pointer, and fou_create dereferences it. Reaching the FOU generic-Netlink path requires a privileged local user; the resulting NULL dereference interrupts the system.

The record

CVE
CVE-2026-23439
Published
Apr 3, 2026
Updated
Apr 3, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Apr 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 3, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.18
  2. Affected versionversion=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <003343985f26dfefd0c94b1fe1316a2de74428b9
  3. Affected versionversion=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <12aa4b73a67d95bc739995a2d6943aec2f9785c9
  4. Affected versionversion=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <9f036aa0fe46c19e938f03d10e02c23f4fffae5e
  5. Affected versionversion=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <a05a2149386f6dfb4245f522acdbef892acafc84
  6. Affected versionversion=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <b3a6df291fecf5f8a308953b65ca72b7fc9e015d
  7. Affected versionversion=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <ba7c9ddcdd077942b798979edb035207374d4096

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.18; version=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <003343985f26dfefd0c94b1fe1316a2de74428b9; version=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <12aa4b73a67d95bc739995a2d6943aec2f9785c9; version=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <9f036aa0fe46c19e938f03d10e02c23f4fffae5e; version=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <a05a2149386f6dfb4245f522acdbef892acafc84; version=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <b3a6df291fecf5f8a308953b65ca72b7fc9e015d; version=fd384412e199b62c3ddaabd18dce86d0e164c5b9 <ba7c9ddcdd077942b798979edb035207374d4096

Published CVSS scores

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004System or Application 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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