CVE-2024-50253

A flaw was found in the Linux kernel. A privileged local user could exploit a missing validity check for the nr_words parameter within the Berkeley Packet Filter (BPF) subsystem's bpf_iter_bits_new() function. This could lead to a multiplication overflow, resulting in stack corruption and a denial of service.

The default Red Hat Enterprise Linux kernel prevents unprivileged users from being able to use eBPF by the kernel.unprivileged_bpf_disabled sysctl. This would require a privileged user with CAP_SYS_ADMIN or root to be able to abuse this flaw reducing its attack space.

For the Red Hat Enterprise Linux 9 to confirm the current state, inspect the sysctl with the command:

cat /proc/sys/kernel/unprivileged_bpf_disabled

The setting of 1 would mean that unprivileged users can not use eBPF, mitigating the flaw.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To confirm that unprivileged users cannot utilize eBPF, inspect the kernel.unprivileged_bpf_disabled sysctl. A value of 1 indicates that unprivileged eBPF is disabled, which mitigates this flaw. If the value is 0, set it to 1 using sysctl -w kernel.unprivileged_bpf_disabled=1 and ensure this setting persists across reboots by adding kernel.unprivileged_bpf_disabled = 1 to /etc/sysctl.d/99-sysctl.conf.