CVE-2026-98378

A flaw was found in the Linux kernel's Berkeley Packet Filter (BPF) subsystem. A local attacker can trigger a use-after-free flaw by iterating over BPF links while a concurrent link creation operation fails. This issue occurs because the iterator references links before their initialization is complete, leading to freed memory being accessed if the creation aborts. A local user could exploit this flaw to cause a system crash, resulting in a Denial of Service (DoS), or potentially execute arbitrary code.

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.