CVE-2026-74573

A flaw was found in the Linux kernel's ARM System Memory Management Unit version 3 (SMMUv3) IOMMU driver. This vulnerability occurs because the driver incorrectly assumes that a virtual device (vDEVICE) has only one Stream ID. This can lead to a guest operating system's virtual Stream ID invalidation failing to clear all relevant entries, potentially resulting in information disclosure or data integrity issues. Additionally, if a virtual device has no streams, an out-of-bounds read can occur, which may lead to a denial of service.

This vulnerability is rated as Important severity because an unprivileged or guest-level attacker can trigger memory safety violations or translation cache desynchronization across virtual device mappings, potentially compromising system integrity or causing a host kernel denial of service. The risk is limited to ARM64 deployments utilizing virtual device pass-through managed via the IOMMUFD subsystem. Standard enterprise workloads on other hardware architectures or systems not employing ARM vSMMU virtualization features are unaffected.

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.