CVE-2026-97593
Description
A flaw was found in the Linux kernel's s390 IOMMU (Input-Output Memory Management Unit) driver. When performing address translation for an unmapped I/O virtual address on systems configured with five-level translation tables, the driver fails to verify whether a region table pointer is valid before accessing it. A local user can exploit this vulnerability to trigger a NULL pointer dereference, causing a kernel crash and resulting in a Denial of Service (DoS).
Statement
A low impact NULL pointer dereference flaw was found in the Linux kernel's s390 IOMMU driver. When iova_to_phys() performs address translation for an unmapped I/O virtual address (IOVA) on a system configured with five-level translation tables (ZPCI_TABLE_TYPE_RFX), the region-second origin pointer returned by get_rso_from_iova() is dereferenced in get_rto_from_iova() without first being checked for NULL. A local user on an affected s390 (IBM Z) system could use this flaw to crash the kernel, resulting in a denial of service. Confidentiality and integrity are not impacted. This flaw affects the kernel shipped in Red Hat Enterprise Linux 9 and Red Hat Enterprise Linux 10, Red Hat In-Vehicle OS 2, and Red Hat OpenShift Container Platform releases based on RHEL 9 CoreOS. Red Hat Enterprise Linux 6, 7, and 8 are not affected because the vulnerable code is not present in their kernels. For the affected products this issue has been deferred: it is a low impact, local denial of service that requires access to an s390 system configured with five-level translation tables, so the fix will be delivered in a future scheduled kernel update. The residual risk is limited to kernel availability on affected s390 systems.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | N/A | N/A |
| Attack Vector | Local | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | Low | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | None | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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