CVE-2026-98039

A flaw was found in the Linux kernel's BPF (Berkeley Packet Filter) verifier. The verifier improperly validates pointer types when storing values into per-CPU map fields, allowing standard memory allocations or kernel pointers to be accepted as per-CPU data. A local user with permissions to load BPF programs could exploit this vulnerability to perform arbitrary kernel memory reads and writes, potentially resulting in privilege escalation or a Denial of Service (DoS) caused by a system crash.

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 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.

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.