CVE-2026-64152
Received Received - Intake

IOMMU Map Error Handling in Linux Kernel

Publication date: 2026-07-19

Last updated on: 2026-07-19

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: iommu: Handle unmap error when iommu_debug is enabled Sashiko noticed a latent bug where the map error flow called iommu_unmap() which calls iommu_debug_unmap_begin()/iommu_debug_unmap_end() however since this is an error path the map flow never actually established the original iommu_debug_map() it will malfunction. Lift the unmap error handling into iommu_map_nosync() and reorder it so the trace_map()/iommu_debug_map() records the partial mapping and then immediately unmaps it. This avoid creating the unbalanced tracking and provides saner tracing instead of a unmap unmatched to any map.

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Meta Information

Published
2026-07-19
Last Modified
2026-07-19
Generated
2026-07-20
AI Q&A
2026-07-19
EPSS Evaluated
N/A
NVD
CVE-2026-64152
EUVD
EUVD-2026-45837

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux_kernel linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves improper handling of unmap errors when iommu_debug is enabled. A bug exists where an error in the map flow calls iommu_unmap() without a prior iommu_debug_map(), causing unbalanced tracking and incorrect tracing.

Detection Guidance

This vulnerability is specific to the Linux kernel's IOMMU subsystem and may not have direct network detection methods. Check kernel logs for IOMMU-related errors using dmesg | grep -i iommu or journalctl -k | grep -i iommu. Monitor for unmap errors or trace mismatches in IOMMU operations.

Impact Analysis

This vulnerability may lead to incorrect IOMMU debugging logs and potential system instability if unmap operations occur without corresponding map operations. It could affect systems using IOMMU debugging features.

Compliance Impact

This vulnerability does not directly affect compliance with standards like GDPR or HIPAA as it pertains to a low-level kernel memory management issue in the IOMMU subsystem. No evidence suggests data exposure or privacy violations.

Mitigation Strategies

Update the Linux kernel to the latest stable version that includes the fix for this vulnerability. If immediate patching is not possible, disable iommu_debug by setting iommu.debug=0 in kernel parameters as a temporary workaround.

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