CVE-2023-52581: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-52581 affects the Linux kernel's nftables sub-component, specifically related to a memory leak vulnerability discovered in the netfilter component. The issue was identified when more than 255 elements expired in the garbage collection (GC) container structure. The vulnerability was disclosed on March 2, 2024, affecting various Linux kernel versions (NVD, Red Hat).

The vulnerability occurs due to a type wrapping issue in the nftables garbage collection mechanism. When more than 255 elements expire, the system is supposed to switch to a new GC container structure. However, due to the use of a u8 type for the counter, it wraps before reaching the boundary, causing nfttransgc_space() to always return true. This results in recycling the initial GC container structure and losing track of previously expired elements (Kernel Commit). The vulnerability has been assigned a CVSS v3.1 base score of 6.3 (Medium) by CISA-ADP (NVD).

The vulnerability can lead to memory leaks in the Linux kernel's netfilter subsystem. This flaw allows a local attacker with CAPNETADMIN access privilege in any user or network namespace to potentially crash the system. The issue is similar to the previous CVE-2023-4244 but affects a different part of the source code (Red Hat).

For non-containerized deployments of Red Hat Enterprise Linux, administrators can disable user namespaces by setting user.maxusernamespaces to 0. However, this mitigation should not be applied to containerized deployments such as Red Hat OpenShift Container Platform where the functionality needs to remain enabled. Alternatively, administrators can blacklist the affected 'nftables' module to prevent it from loading at boot time until a fix is available (Red Hat).