CVE-2026-89570

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

cxl/mce: Make the MCE notifier per-region

Flavien Solt reported lifetime issues with the CXL MCE notifier, which

can lead to NULL dereferences and use-after-free in the MCE handler.

The notifier was registered per memory device and stored in 'struct

cxl_memdev_state', even though it only needs the region state (the

region's SPA range and its extended linear cache size).

Instead of keeping the memory device and endpoint alive, the correct fix

is to move the notifier into 'struct cxl_region' and register it from

cxl_region_probe() as it should be a per-region notifier. Setup the

registration to only happen for regions that have an extended linear

cache as that is the only current usage.

Remove cxl_port_get_spa_cache_alias() as it is now dead code.

[ dj: Update dev_warn() when notifier fails due to kconfig. (Ben) ]

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References