CVE-2026-99074
kernel: ipv4: stop PMTU walk when nexthop group shrinks
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · October 23, 2026
Updated · October 26, 2026
Description
A flaw was found in the Linux kernel's IPv4 networking subsystem. A race condition can occur when updating Path Maximum Transmission Unit (PMTU) routes while next-hop routing groups are simultaneously reduced in size. A local user with network administration privileges, or an unprivileged user where user namespaces are enabled, can trigger a NULL pointer dereference that crashes the system, resulting in a Denial of Service (DoS).
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CWE-476 · NULL Pointer Dereference