Bug 2516855 (CVE-2026-74355)

Summary: CVE-2026-74355 kernel: iommu/vt-d: Fix RB-tree corruption in probe error path
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's iommu/vt-d component. This vulnerability occurs when the info->node RB-tree member is zero-initialized, and a device that does not support Address Translation Services (ATS) skips the device_rbtree_insert() call. If a subsequent probe step fails, the error path incorrectly attempts to remove a zeroed node, misinterpreting it as a tree root. This misinterpretation leads to corruption of the device RB-tree, which can result in system instability or a denial of service.
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Description OSIDB Bzimport 2026-08-15 06:37:01 UTC 
In the Linux kernel, the following vulnerability has been resolved:

iommu/vt-d: Fix RB-tree corruption in probe error path

The info->node RB-tree member is zero-initialized via kzalloc. If
a device does not support ATS, the device_rbtree_insert() call is
skipped. If a subsequent probe step fails, the error path jumps to
device_rbtree_remove(), which misinterprets the zeroed node as
a tree root and corrupts the device RB-tree.

Fix this by explicitly initializing the RB-node as empty using
RB_CLEAR_NODE() during initialization and guarding the removal with
RB_EMPTY_NODE().
Comment 1 gkamathe 2026-08-19 12:33:11 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081500-CVE-2026-74355-99a3@gregkh/T