SB2026102385 - NULL pointer dereference in Linux kernel ipv4

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Main Vulnerability Database SB2026102385

SB2026102385 - NULL pointer dereference in Linux kernel ipv4

Published: October 23, 2026

Security Bulletin ID SB2026102385
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) NULL pointer dereference (CVE-ID: CVE-2026-99074)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: 5.7 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to cause a denial of service by triggering a kernel NULL pointer dereference.

The vulnerability exists due to a NULL pointer dereference in the IPv4 PMTU update path in net/ipv4/route.c when a nexthop group shrinks during path iteration. A local user can replace a nexthop group concurrently with PMTU updates so that fib_info_nhc() returns NULL for a previously accepted index, causing update_or_create_fnhe() to dereference it and crash the kernel.

Nexthop group replacement requires CAP_NET_ADMIN in the network namespace. Where unprivileged user namespaces are permitted, this capability can be obtained in a new user and network namespace.


Remediation

Install update from vendor's website.

References