CVE-2026-64291

Analyzed Analyzed - Analysis Complete

Memory Exhaustion in Linux Kernel iommufd

Publication date: 2026-07-25

Last updated on: 2026-08-12

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: iommufd: Set veventq_depth upper bound iommufd_veventq_alloc() accepts any !0 veventq_depth from userspace, with an upper bound at U32_MAX. This leaves a vulnerability where userspace can allocate excessively large queues to exhaust kernel memory reserves. Cap the veventq_depth (maximum number of entries) to 1 << 19, matching the maximum number of entries in the SMMUv3 EVTQ (the largest use case today).

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-07-25

Last Modified

2026-08-12

Generated

2026-08-14

AI Q&A

2026-07-25

EPSS Evaluated

2026-08-13

NVD

CVE-2026-64291

EUVD

EUVD-2026-49003

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	From 6.19 (inc) to 7.1.4 (exc)
linux	linux_kernel	From 6.15 (inc) to 6.18.39 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability in the Linux kernel involves the iommufd component, where userspace can allocate excessively large queues in the veventq_depth parameter. The issue arises because the function iommufd_veventq_alloc() accepts any non-zero value for veventq_depth up to U32_MAX, allowing userspace to exhaust kernel memory reserves by creating very large queues.

Detection Guidance

This vulnerability involves excessive queue allocation in the Linux kernel's iommufd component. Detection requires checking kernel logs for unusually large iommufd allocations or memory exhaustion events. Monitor for kernel messages indicating high memory usage or failed allocations in iommufd-related subsystems.

Impact Analysis

This vulnerability can lead to kernel memory exhaustion, causing system instability, crashes, or denial-of-service conditions. Attackers with local access could exploit it to degrade system performance or render services unavailable.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it is a kernel memory exhaustion issue rather than a data protection or privacy breach. However, if exploited, it could lead to system instability or denial of service, potentially impacting availability requirements under these regulations.

Mitigation Strategies

Update your Linux kernel to the patched version that includes the fix for CVE-2026-64291. The patch caps the veventq_depth to 1 << 19 to prevent excessive queue allocations. Check your distribution's security updates or kernel release notes for the specific version containing this fix.

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