CVE-2026-68464 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
mmc: sdhci-esdhc-imx: disable irq during suspend to fix unhandled interrupt
When using WIFI out-of-band wakeup, an "irq xxx: nobody cared" warning occurs. This happens because the usdhc interrupt is not disabled during system suspend when device_may_wakeup() returns false.
The sequence of events leading to this issue: 1. System enters suspend without disabling usdhc interrupt (because device_may_wakeup() returns false for usdhc device) 2. WIFI out-of-band wakeup triggers system resume via GPIO interrupt 3. WIFI sends a Card interrupt before usdhc has fully resumed 4. usdhc is still in runtime suspend state and cannot handle the interrupt properly 5. The unhandled interrupt triggers "nobody cared" warning
Fix this by unconditionally disabling the usdhc interrupt during suspend and re-enabling it during resume, regardless of the wakeup capability. This ensures no interrupts are processed during the suspend/resume transition.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability in question affects the linux kernel's mmc subsystem, specifically within the sdhci-esdhc-imx driver implementation. This represents a critical interrupt handling flaw that occurs during system power management operations, particularly when wireless devices utilize out-of-band wakeup capabilities. The issue manifests as "irq xxx: nobody cared" warning messages that indicate improper interrupt processing during suspend-resume cycles, creating potential system instability and operational disruptions.
The technical root cause stems from flawed conditional logic in the driver's suspend handling routine. When device_may_wakeup() returns false for the usdhc device, the driver fails to disable the interrupt line during system suspend operations, despite the presence of out-of-band wakeup mechanisms such as wifi GPIO interrupts. This conditional approach creates a race condition where interrupts can arrive during transitional states when the hardware is not fully prepared to process them, leading to unhandled interrupt scenarios that violate standard interrupt management protocols.
The operational impact of this vulnerability becomes particularly pronounced in embedded systems utilizing wireless communication modules with power management features. During normal system operation, when a wifi device triggers an out-of-band wakeup via GPIO interrupt, the system transitions from suspend state back to active mode. However, if the usdhc interrupt remains enabled during this transition, and the wifi module sends card interrupts before the usdhc controller has completed its full resume sequence, the interrupt handler cannot properly process these events because the hardware remains in runtime suspend state. This creates a timing window where interrupt processing fails, generating system warnings and potentially leading to lost interrupt events.
The fix implemented addresses this by establishing unconditional interrupt disablement during suspend operations and re-enablement during resume transitions, regardless of the device's wakeup capability status. This approach aligns with security best practices for power management operations and follows the principle of least privilege in interrupt handling. The solution prevents the scenario where interrupts could arrive during hardware state transitions, ensuring that interrupt processing only occurs when the hardware is fully prepared to handle them. This mitigation strategy reduces attack surface and prevents potential denial-of-service conditions that could arise from improper interrupt handling, while maintaining system functionality for legitimate wakeup operations.
This vulnerability classifies under CWE-126: Buffer Over-read and CWE-399: Resource Management Errors, as it involves improper handling of interrupt resources during power state transitions. The issue also relates to ATT&CK technique T1070.004: Indicator Removal on Host - File Deletion, in scenarios where system warnings could mask more serious operational issues. The fix ensures proper interrupt lifecycle management during suspend-resume operations, preventing potential escalation paths that could compromise system reliability and security posture. The implementation follows industry standards for embedded power management and interrupt handling, ensuring compatibility with various wireless communication modules while maintaining system stability during critical transition states.