CVE-2024-49888 is a vulnerability in the Linux kernel's Berkeley Packet Filter (BPF) subsystem related to signed division (sdiv) and signed modulo (smod) operations. The issue arises from an integer overflow during signed division when the divisor is -1 and the dividend is the minimum signed integer value (LLONG_MIN for 64-bit or INT_MIN for 32-bit). Specifically, dividing LLONG_MIN (-9,223,372,036,854,775,808) by -1 should yield a positive number 9,223,372,036,854,775,808, but this exceeds the maximum positive value for a signed 64-bit integer (9,223,372,036,854,775,807), causing an arithmetic overflow. On x86_64 architectures, this results in a kernel exception (crash), while on arm64, the operation returns LLONG_MIN without exception. The vulnerability affects all sdiv and smod operations in BPF programs where the divisor is -1 or 0, potentially causing kernel crashes on x86_64 systems. The patch involves instruction patching to handle these edge cases safely, aligning the behavior with arm64 results, and preventing kernel exceptions by adding conditional checks and adjustments before performing division or modulo operations. This vulnerability was reported by Zac Ecob and is fixed in recent Linux kernel versions. No known exploits are currently reported in the wild. The vulnerability impacts the stability and reliability of the Linux kernel when running BPF programs that perform these arithmetic operations, potentially leading to denial of service (kernel crash).

For European organizations, this vulnerability poses a risk primarily to systems running Linux kernels with vulnerable BPF implementations on x86_64 platforms. Since BPF is widely used for network packet filtering, monitoring, and security enforcement, exploitation or accidental triggering of this bug can cause kernel panics and system crashes, leading to denial of service. This can disrupt critical infrastructure, cloud services, and enterprise environments relying on Linux servers. Organizations using container orchestration platforms, cloud-native applications, or network security tools that leverage BPF could experience service interruptions. Although no active exploits are known, the vulnerability's presence increases the attack surface for denial-of-service attacks. The impact on confidentiality and integrity is limited, as the vulnerability causes crashes rather than privilege escalation or data leakage. However, availability impact can be significant, especially for high-availability systems and critical services. The risk is heightened in environments where untrusted or semi-trusted users can load or execute BPF programs, such as multi-tenant cloud platforms or shared hosting.

European organizations should prioritize updating their Linux kernels to versions that include the patch for CVE-2024-49888. Kernel upgrades should be tested and deployed promptly, especially on x86_64 systems running workloads that utilize BPF programs. Additionally, organizations should audit and restrict the ability to load or run untrusted BPF programs by enforcing strict access controls and capabilities (e.g., limiting CAP_BPF and CAP_SYS_ADMIN privileges). Employing kernel lockdown features and seccomp filters can reduce the risk of malicious or malformed BPF programs triggering this vulnerability. Monitoring kernel logs for Oops or divide error messages can help detect attempts to exploit or accidentally trigger the bug. For environments where immediate patching is not feasible, temporarily disabling or restricting BPF usage may be considered, though this may impact functionality. Finally, organizations should maintain an up-to-date inventory of Linux kernel versions in use and apply security patches as part of their regular vulnerability management process.