CVE-2026-64254

A flaw was found in the Linux kernel's Non-Transparent Bridge (NTB) endpoint driver. A local user could cause a Denial of Service (DoS) during module unloading when configuration and scratchpad resources share the same PCI Base Address Register (BAR). In this scenario, the driver improperly attempts to release mapped memory at an offset, resulting in an invalid unmapping operation that can trigger kernel warnings and system instability.

Red Hat has evaluated this flaw as having a Low security impact because triggering the condition requires local administrative access to unbind hardware or unload kernel drivers on specialized Non-Transparent Bridge (NTB) endpoint hardware. The improper unmapping sequence occurs exclusively during module teardown when specific PCI memory configurations overlap, generating kernel warnings rather than arbitrary code execution. Furthermore, the affected driver is not active in default installations, severely limiting exposure across standard deployments.

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.