Linux Kernel Multiple Versions Netlink Namespace Cleanup Vulnerability Leading to Denial-of-Service

A vulnerability in the Linux kernel's IP multicast routing (IPMR) netlink namespace cleanup process can cause a kernel panic. This issue arises when the kernel is built without support for multiple IP routing tables, leading to an inadequate sanity check during netlink namespace operations. The vulnerability was triggered by a warning related to the IPMR rules exit function, indicating a problem with freeing IPMR tables in the network namespace cleanup.

Impact

The vulnerability causes a kernel panic, disrupting system operations and potentially leading to a denial-of-service condition.

Reproduction

The vulnerability can be reproduced by unsharing a netlink namespace in a Linux kernel version 6.14.0 that is not configured to support multiple IP routing tables. This can be done using the 'unshare' command, which creates a new process with a different set of namespaces, effectively isolating it from the main process.

Remediation

Users can upgrade to the latest stable version of the Linux kernel, where this vulnerability has been addressed.