CVE-2023-53133: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-53133 is a vulnerability in the Linux kernel affecting the BPF (Berkeley Packet Filter) and sockmap functionality. The issue was discovered and reported in May 2025, specifically related to an infinite loop error when the buffer length of the recvmsg system call is 0 in the tcp_bpf_recvmsg_parser() function (NVD).

The vulnerability occurs in the tcp_bpf_recvmsg_parser function when handling zero-length buffer requests. The logic follows a pattern where if no data is copied (copied = 0), it enters a wait state and loops back, creating an infinite loop condition. This results in a soft lockup of the CPU, as evidenced by the watchdog detecting a CPU being stuck for 27 seconds. The issue manifests in Linux kernel version 6.2.0+ and affects the tcp_bpf_recvmsg_parser() implementation (RedHat).

The vulnerability can cause a system CPU to enter a soft lockup state, effectively freezing one CPU core and potentially impacting system performance and stability. This occurs when specific conditions are met during network packet processing using BPF sockmap functionality (NVD).

The vulnerability has been fixed in various Linux kernel versions. Debian has addressed this in version 6.1.137-1 for bookworm and 6.12.27-1 for trixie and sid releases. The fix involves modifying the tcp_bpf_recvmsg_parser() function to properly handle zero-length buffer cases by returning immediately instead of entering the wait loop (Debian).