CVE-2026-45862
Description
A flaw was found in the Linux kernel's IOMMU (Input/Output Memory Management Unit) virtualized directed I/O (VT-d) component. When a freshly allocated PASID (Process Address Space ID) table is written to a directory entry, the CPU cache flush for this table occurs too late. This creates a time window where non-coherent IOMMU hardware might use the PASID table while its contents in memory are still uninitialized or contain old, random data. This could lead to data integrity issues or system instability.
Statement
This vulnerability is rated as having a Moderate impact by Red Hat because exploitation requires local access on systems operating with non-coherent Intel VT-d hardware supporting Process Address Space ID (PASID), with consequences limited to denial of service or memory corruption. The timing window for unsynchronized cache lines arises specifically during dynamic PASID directory initialization. Deployments not utilizing scalable-mode Intel IOMMU features or running on coherent architectures are not exposed to this issue.
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 | 7.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | High |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Changed |
| Confidentiality | None | N/A | High |
| Integrity Impact | None | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
Understanding the Weakness (CWE)
Integrity,Confidentiality,Other
Technical Impact: Modify Application Data; Read Application Data; Alter Execution Logic; Unexpected State
If access to a shared resource is not correctly synchronized, then the resource may not be in a state that is expected by the product. This might lead to unexpected or insecure behaviors, especially if an attacker can influence the shared resource.
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