Bug 2502579 (CVE-2026-64152)

Summary: CVE-2026-64152 kernel: iommu: Handle unmap error when iommu_debug is enabled
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's Input/Output Memory Management Unit (IOMMU) subsystem when `iommu_debug` is enabled. This issue occurs because an error handling path attempts to unmap memory without a proper initial mapping, leading to an inconsistent state within the IOMMU's debugging and tracing mechanisms. This malfunction could result in unbalanced tracking, potentially affecting system stability or the accuracy of IOMMU debugging information.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-07-19 17:07:09 UTC 
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.
Comment 1 TEJ RATHI 2026-07-20 07:42:55 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026071931-CVE-2026-64152-0751@gregkh/T