CVE-2026-72453

A flaw was found in the Linux kernel's regcache mechanism. During initialization, an error in a specific callback function (cache_ops->populate) can have its error code overwritten by a subsequent exit routine. This masks the original error, potentially causing the system to attempt operations on uninitialized memory. Such actions can result in NULL pointer dereferences, leading to system instability or a denial of service.

A flaw was found in the Linux kernel's regcache (register map cache) mechanism. During regcache initialization, if an error occurs in the cache_ops->populate callback and the cache operations include an exit callback, the error code from populate() is overwritten by the return value of exit(). As a result, regcache_init() can incorrectly report success even though the cache was not populated, and later access to the regcache can result in a NULL pointer dereference, leading to a kernel panic and denial of service. Triggering this flaw requires local access and depends on a specific regmap-based driver and cache configuration in which the populate callback fails; there is no impact on confidentiality or integrity.

The vulnerable code, introduced when the ->populate() callback was added to regcache, is present only in Red Hat Enterprise Linux 9.9, Red Hat Enterprise Linux 10.3, and Red Hat In-Vehicle OS 2 streams (kernel and kernel-ivos-qualcomm components). Other Red Hat Enterprise Linux versions and update streams (RHEL 6 through RHEL 10.2, including their z-streams) do not contain the vulnerable code and are therefore not affected.

For the affected streams, the fix is deferred to a future update because this is a low-impact issue; the residual risk is a kernel panic (denial of service) if a regmap driver's cache population fails during initialization. Although the CVSS:3.1 base score is 5.5 (Moderate), Red Hat assesses the impact of this flaw as Low because it is not remotely exploitable, requires specific local conditions during driver initialization, and affects only system availability.

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.