Bug 2507286 (CVE-2026-64290)

Summary: CVE-2026-64290 kernel: iommufd: Break the loop on failure in iommufd_fault_fops_read()
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
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's `iommufd` component. When a `copy_to_user()` operation fails within the `iommufd_fault_fops_read()` function, the system enters an infinite loop. This continuous retry consumes 100% of the CPU and holds a mutex, which can lead to a denial of service (DoS) for affected systems.
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Description OSIDB Bzimport 2026-07-25 10:14:36 UTC 
In the Linux kernel, the following vulnerability has been resolved:

iommufd: Break the loop on failure in iommufd_fault_fops_read()

On a copy_to_user() failure inside the inner list_for_each_entry, only the
inner loop breaks; the outer while re-fetches the just-restored fault group
and retries the failing copy_to_user() forever, spinning the reader at 100%
CPU with fault->mutex held.

Check rc after the inner loop and break the outer while as well.
Comment 1 TEJ RATHI 2026-07-27 07:58:16 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072504-CVE-2026-64290-6522@gregkh/T