CVE-2024-53680 is a vulnerability in the Linux kernel's IP Virtual Server (IPVS) subsystem, specifically in the function ip_vs_protocol_init(). The issue arises due to undefined behavior caused by the use of an uninitialized on-stack buffer of 64 bytes intended to store registered protocol names. When the Linux kernel is compiled with Clang/LLVM under certain configurations, the compiler fails to generate a proper return or jump instruction at the end of ip_vs_protocol_init(), leading to a fall-through into the next function. This is triggered by the compiler's optimization passes interpreting the uninitialized stack memory as undefined, which results in the removal of necessary code and the absence of a function terminator. At runtime, this can cause a kernel oops (crash) when loading the ipvs module or a boot-time panic if ipvs is built into the kernel. The root cause is the uninitialized buffer being passed to strnlen() with CONFIG_FORTIFY_SOURCE enabled, which performs additional checks on the buffer's last byte. The fix involves zeroing out the on-stack buffer to eliminate the undefined behavior and ensure proper code generation. This vulnerability affects Linux kernel versions identified by the commit hash 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and is relevant for systems using Clang/LLVM to compile the kernel with IPVS enabled. No known exploits are reported in the wild yet.

The vulnerability can cause system instability or denial of service due to kernel panics or oops events during boot or module loading. For European organizations relying on Linux servers, especially those using IPVS for load balancing or high availability in data centers or cloud environments, this could lead to unexpected downtime and service interruptions. Critical infrastructure, telecommunications, and cloud service providers using affected Linux kernels compiled with Clang/LLVM are at risk of operational disruption. Although this vulnerability does not directly enable privilege escalation or remote code execution, the resulting denial of service can impact availability and potentially lead to cascading failures in dependent services. Organizations with automated kernel builds using Clang/LLVM and IPVS enabled are particularly vulnerable. The lack of a CVSS score and no known exploits suggest the threat is currently low in exploitation but could become more severe if attackers develop methods to trigger the kernel panic remotely or in multi-tenant environments.

1. Apply the official Linux kernel patch that zeroes the on-stack buffer in ip_vs_protocol_init() to eliminate undefined behavior. 2. Rebuild the Linux kernel using updated source code with the fix applied, especially if compiling with Clang/LLVM and IPVS enabled. 3. If immediate patching is not possible, consider disabling the IPVS module or rebuilding the kernel with GCC instead of Clang/LLVM as a temporary workaround. 4. Implement rigorous kernel build and test procedures to detect objtool warnings and undefined behavior during compilation. 5. Monitor system logs for kernel oops or panic events related to IPVS module loading and investigate any anomalies promptly. 6. For production environments, ensure redundancy and failover mechanisms are in place to mitigate potential downtime caused by kernel crashes. 7. Engage with Linux distribution vendors for timely updates and backported patches to minimize exposure. 8. Review kernel build configurations to avoid enabling CONFIG_FORTIFY_SOURCE in combination with Clang/LLVM if not necessary, or ensure patches are applied before enabling these features.