CVE-2026-89745

A flaw was found in the Linux kernel's debugfs component. The lockdown mechanism, designed to enhance system integrity, did not properly account for files using the mmap_prepare operation. This oversight could allow an attacker to bypass kernel lockdown restrictions when the system is operating in integrity mode, potentially compromising system integrity.

A moderate impact flaw was found in the Linux kernel's debugfs component. The debugfs lockdown check only inspected the mmap file operation, so when files such as relayfs were converted to the mmap_prepare operation, debugfs was not locked down when the kernel operated in lockdown integrity mode. A local attacker with access to an affected debugfs file that uses mmap_prepare but not mmap could bypass kernel lockdown restrictions and potentially compromise system integrity. Red Hat Enterprise Linux 7, 8, 9, and 10 (kernel and kernel-rt) are not affected because the vulnerable code, introduced upstream in the 6.19 kernel, is not present in those streams; OpenShift Container Platform 4 RHEL CoreOS 8 and 9 images are likewise not affected. OpenShift Container Platform 5.0 and 5.1 (RHEL CoreOS 9) are affected and the fix is currently deferred for those streams; until a fixed kernel is delivered, systems running an affected kernel in lockdown integrity mode remain exposed to this lockdown bypass by local attackers.

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.