CVE-2026-93256
Received Received - Intake

Kernel DAIF Masking Issue in Linux arm64 Hibernation

Publication date: 2026-09-24

Last updated on: 2026-09-24

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: arm64: hibernate: mask DAIF before restoring hibernated kernel The arm64 hibernate code manages the exception masking in an unsound way, leading to potential crashes and/or warnings during resume. When a hibernation image is saved in `swsusp_arch_suspend()`, all DAIF exceptions are masked (by virtue of `local_daif_save()`), and the suspended image is saved assuming that all DAIF exceptions will remain masked when the image is restored. When a hibernation image is resumed by `swsusp_arch_resume()`, only interrupts are masked (by virtue of `local_irq_disable()` in `resume_target_kernel()`). When pseudo-NMI is enabled the DAIF.IF bits will be clear, and regardless of pseudo-NMI the DAIF.DA bits will be clear. This means that there are two problems: (1) It is possible to take Debug, SError, or pseudo-NMI exceptions during the resume process. This is unsafe, as during the resume process both the old ane new kernels will tranisently be in an inconsistent state, and swsusp_arch_suspend_exit() won't retain an executable mapping of any exception vectors. Any exception taken here will be fatal and silent. (2) When re-entering the resumed kernel, some DAIF bits will be clear unexpectedly. This permits Debug, SError, or pseudo-NMI exceptions to be taken for a short period while the resumed kernel is not yet in a consistent state. This is detected by CONFIG_ARM64_DEBUG_PRIORITY_MASKING. Avoid these issues by masking all DAIF exceptions during resume.

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Meta Information

Published
2026-09-24
Last Modified
2026-09-24
Generated
2026-09-25
AI Q&A
2026-09-24
EPSS Evaluated
N/A
NVD
CVE-2026-93256
EUVD
EUVD-2026-86128

Affected Vendors & Products

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

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability affects the Linux kernel's arm64 hibernation feature. The issue is that exception masking is handled incorrectly during system resume from hibernation. When saving a hibernation image, all exceptions are masked, but during resume only interrupts are masked. This leaves the system vulnerable to unexpected exceptions like Debug, SError, or pseudo-NMI during the inconsistent state between old and new kernels, which can cause crashes or silent failures.

Detection Guidance

This vulnerability affects the Linux kernel's arm64 hibernation process. Detection requires checking kernel logs for hibernation-related crashes or warnings during resume. Look for messages indicating DAIF exception handling issues or CONFIG_ARM64_DEBUG_PRIORITY_MASKING warnings.

Impact Analysis

If you use a Linux system with arm64 architecture and hibernation enabled, this vulnerability could cause your system to crash or become unresponsive during resume from hibernation. It may also lead to data corruption or silent failures without clear error messages, making recovery difficult.

Compliance Impact

This vulnerability does not directly affect compliance with GDPR, HIPAA, or similar standards as it pertains to a low-level kernel exception handling issue in Linux. Compliance impacts would only occur if the vulnerability led to data corruption, unauthorized access, or service disruption during system resume operations.

Mitigation Strategies

Apply the latest Linux kernel patches that address the hibernation exception masking issue. Ensure your system is running a kernel version that includes the fix for CVE-2026-93256.

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