CVE-2026-63809

A flaw was found in the Linux kernel. An issue in the BPF (Berkeley Packet Filter) subsystem's sysctl handling can lead to memory corruption. Specifically, when a temporary buffer is allocated using kvzalloc() but incorrectly freed with kfree(), it can corrupt memory. A local attacker could exploit this vulnerability to cause a system crash, leading to a denial of service.

This vulnerability is rated as Moderate severity for Red Hat Enterprise Linux because exploiting it requires privileged access to attach cgroup-scoped BPF programs and write large payloads to sysctl entries, limiting the blast radius to a local denial of service. Under default enterprise configurations, unprivileged users cannot attach control group filters or manipulate protected kernel parameters in a manner that triggers the improper memory deallocation. Consequently, an attacker must already possess administrative privileges on the host system to trigger an unexpected kernel crash.

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.