CVE-2026-89447

Received Received - Intake

iommufd Access Notification Bypass in Linux Kernel

Publication date: 2026-09-11

Last updated on: 2026-09-11

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: iommufd: Avoid locking internal accesses during unmap iommufd_access_notify_unmap() skips internal accesses because they do not have an external unmap callback to invoke. However, the current test calls iommufd_lock_obj() before checking whether the access is internal. If iommufd_lock_obj() succeeds, the loop then sees the internal access and continues, bypassing the matching iommufd_put_object() used by the normal unmap path. This leaks the object reference taken by iommufd_lock_obj(). Check for internal accesses first so skipped entries are never locked.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-09-11

Last Modified

2026-09-11

Generated

2026-10-02

AI Q&A

2026-09-12

EPSS Evaluated

2026-10-01

NVD

CVE-2026-89447

EUVD

EUVD-2026-76353

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves a reference leak in the iommufd component. The issue occurs when iommufd_access_notify_unmap() checks for internal accesses after locking an object, causing skipped entries to remain locked. This leads to a reference leak because the matching iommufd_put_object() call is bypassed.

Detection Guidance

This vulnerability is specific to the Linux kernel's iommufd component and does not have direct network detection methods. Detection involves checking kernel logs for iommufd-related errors or verifying kernel version against patched releases. Use commands like 'dmesg | grep iommufd' or 'uname -r' to check kernel version.

Impact Analysis

This vulnerability could lead to resource exhaustion in the Linux kernel, potentially causing system instability or crashes. It may also allow attackers to manipulate kernel memory by preventing proper cleanup of object references.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it is a low-level kernel memory management issue. Standards like GDPR and HIPAA focus on data protection and privacy, while this CVE relates to a reference leak in the Linux kernel's iommufd subsystem, which does not involve unauthorized data access or exposure.

Mitigation Strategies

Update the Linux kernel to the latest patched version to resolve the iommufd reference leak vulnerability.

Hi! I’m here to help you understand CVE-2026-89447. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70