CVE-2026-90185

A flaw was found in the Linux kernel's null_blk module. This vulnerability occurs because concurrent operations on configfs attributes are not properly synchronized. A local user could exploit this timing issue to modify data during device setup, leading to an out-of-bounds memory access. This could cause system instability or a denial of service.

A race in null_blk configfs attribute stores can allow concurrent writes on separate file descriptors to update device fields while another store is applying queue changes or while power_store is building the device. This can leave software state out of sync with the live queue configuration and can also let zone_nr_conv exceed nr_zones after validation, leading to out of bounds dev zones access. For the CVSS the PR:L is used for the paranoid score because delegated configfs write access or reduced capability admin roles may be enough to race attribute stores, although default host setups usually restrict this interface to administrators. The issue is not network reachable and is triggered through local control plane configuration writes. Impact is at least denial of service via WARN, invalid state, or kernel crash, and worst case may allow limited confidentiality or integrity impact due to a plausible out of bounds memory access candidate.

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 don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.