CVE-2024-53168: 
Linux Kernel vulnerability analysis and mitigation

CVE-2024-53168 is a Use-After-Free (UAF) vulnerability discovered in the Linux kernel's sunrpc kernel TCP socket implementation. The vulnerability was identified in December 2024 and affects Linux kernel versions from 4.2 up to (excluding) 6.6.64, from 6.7 up to (excluding) 6.11.11, and from 6.12 up to (excluding) 6.12.2 (NVD).

The vulnerability occurs when a TCP socket in a network namespace (netns1) is shutdown and closed during xsdestroy operation, but the FIN message with acknowledgment is discarded. This causes the nfsd side to continue sending retransmission messages. When the TCP socket in netns_1 processes the received message, it sends the FIN message in the sending queue and re-establishes the TCP timer. The issue manifests when the network namespace is deleted, causing problems with the net structure accessed by TCP's timer handler function (Kernel Patch). The vulnerability has been assigned a CVSS v3.1 Base Score of 7.8 HIGH with vector: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H (NVD).

The vulnerability can lead to a Use-After-Free condition in the kernel's TCP socket handling, potentially resulting in system crashes, memory corruption, or privilege escalation. This poses significant risks to system stability and security, particularly in environments where network namespaces are frequently created and destroyed (NVD).

The issue has been fixed in the Linux kernel through patches that implement proper network namespace reference counting for TCP kernel sockets. The fix involves holding netns refcnt for the TCP kernel socket as done in other modules. While this is described as an "ugly hack," it can be easily backported to earlier kernels. A more proper fix that cleans up the interfaces is planned but may be more difficult to backport (Kernel Patch).