CVE-2026-90290

What it actually does

The vulnerability leaves the DAIF (interrupt mask) bits in a masked state when swsusp_mte_save_tags() fails during arm64 hibernation, instead of restoring the previously saved state.

Why it matters to the business

Systems may experience unexpected behavior or instability during hibernation attempts that encounter errors, potentially leading to hangs or reduced availability on affected arm64 Linux systems.

How an attack unfolds

An attacker would need to trigger a failure in the memory tag saving function during suspend, which is unlikely without specific conditions, and then the system returns with interrupts disabled, but this is primarily a correctness issue rather than a direct exploit vector.

How to fix it

Apply the upstream kernel patch that restores the saved DAIF state in the error path of swsusp_arch_suspend().

How to confirm the fix worked

Review the kernel source for the presence of DAIF restoration code in the error handling path of hibernation functions.

Typical attack path

1. Trigger error condition in swsusp_mte_save_tags during hibernation
2. Observe return with DAIF masked leading to system instability

How to detect it

Check kernel logs for hibernation errors around suspend attempts; look for signs of system instability post-hibernation errors.

What your security team should do

• Update to a kernel version containing the fix
• Monitor for hibernation-related issues on arm64 systems