CVE-2024-56658: 
Linux Kernel vulnerability analysis and mitigation

A slab-use-after-free vulnerability (CVE-2024-56658) was discovered in the Linux kernel's networking subsystem, specifically in the network namespace dismantling process. The vulnerability was identified in December 2024 and affects multiple versions of the Linux kernel from version 3.12.54 through 6.12.6. The issue occurs in the xfrm6netinit() and xfrm4netinit() functions where network structure might be freed before all destination callbacks are completed (Kernel Patch).

The vulnerability stems from a race condition in the network namespace cleanup process. The issue occurs when xfrm[46]dstopstemplate is copied into net->xfrm.xfrm[46]dstops, but the net structure might be freed before all the dst callbacks are called. When dstdestroy() is later invoked with dst->ops->destroy(dst), it attempts to access dst->ops which points to the already freed net->xfrm.xfrm[46]dstops. This results in a use-after-free condition. The vulnerability has been assigned a CVSS v3.1 base score of 7.8 (HIGH) with vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (NVD).

The vulnerability could allow an attacker to cause a denial of service condition through system crashes or potentially execute arbitrary code. The issue affects the core networking functionality of the Linux kernel, potentially impacting a wide range of Linux-based systems and distributions (Ubuntu Notice).

The vulnerability has been patched in the Linux kernel by implementing a fix that queues the 'struct net' to be freed after another cleanupnet() round and existing rcubarrier(). Users are advised to update their systems to the patched versions. For Ubuntu systems, this requires updating to the specified package versions and performing a system reboot. Third-party kernel modules may need to be recompiled and reinstalled after the update (Ubuntu Notice).