CVE-2009-4272: Linux Kernel

High severity, CVSS 7.5. EPSS: 11.1% chance of exploitation in the next 30 days.

A certain Red Hat patch for net/ipv4/route.c in the Linux kernel 2.6.18 on Red Hat Enterprise Linux (RHEL) 5 allows remote attackers to cause a denial of service (deadlock) via crafted packets that force collisions in the IPv4 routing hash table, and trigger a routing "emergency" in which a hash chain is too long. NOTE: this is related to an issue in the Linux kernel before 2.6.31, when the kernel routing cache is disabled, involving an uninitialized pointer and a panic.

Affected products

• Linux Linux Kernel: version 2.6.18 only
• Red Hat Enterprise Linux Desktop: version 5.0 only
• Red Hat Enterprise Linux Eus: version 5.4 only
• Red Hat Enterprise Linux Server: version 5.0 only
• Red Hat Enterprise Linux Workstation: version 5.0 only
• Red Hat Virtualization: version 5.0 only

Published 2010-01-27. Last modified 2026-06-16.