CVE-2026-46292 in Linux
Summary
by MITRE • 06/08/2026
In the Linux kernel, the following vulnerability has been resolved:
pmdomain: core: Fix detach procedure for virtual devices in genpd
If a device is attached to a PM domain through genpd_dev_pm_attach_by_id(), genpd calls pm_runtime_enable() for the corresponding virtual device that it registers. While this avoids boilerplate code in drivers, there is no corresponding call to pm_runtime_disable() in genpd_dev_pm_detach().
This means these virtual devices are typically detached from its genpd, while runtime PM remains enabled for them, which is not how things are designed to work. In worst cases it may lead to critical errors, like a NULL pointer dereference bug in genpd_runtime_suspend(), which was recently reported. For another case, we may end up keeping an unnecessary vote for a performance state for the device.
To fix these problems, let's add this missing call to pm_runtime_disable() in genpd_dev_pm_detach().
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Analysis
by VulDB Data Team • 06/08/2026
The vulnerability described represents a critical runtime power management flaw within the Linux kernel's generic power domain framework known as genpd. This issue stems from an incomplete implementation of the device detachment procedure that affects how virtual devices are managed within power domain contexts. The problem manifests when devices are attached to power domains using the genpd_dev_pm_attach_by_id() function, which automatically enables runtime power management for the corresponding virtual device through pm_runtime_enable() calls. However, the complementary cleanup function genpd_dev_pm_detach() fails to invoke the necessary pm_runtime_disable() routine, creating a fundamental mismatch in the power management state handling.
The technical flaw specifically addresses a design inconsistency in the genpd subsystem's device lifecycle management. When virtual devices are attached to power domains, the framework correctly enables runtime power management to handle device power states during runtime operations. Yet during the detachment phase, the system fails to properly disable this runtime power management functionality, leaving devices in an inconsistent power state. This improper state management creates a scenario where virtual devices remain registered with runtime power management enabled even after they have been logically detached from their power domain, violating fundamental power management design principles and creating potential for system instability.
The operational impact of this vulnerability extends beyond simple resource management inefficiencies to potentially critical system failures. The most severe consequence involves a NULL pointer dereference bug that can occur within the genpd_runtime_suspend() function when attempting to suspend devices that have been improperly detached from their power domain. This type of error represents a classic security vulnerability that could be exploited to cause system crashes or potentially enable privilege escalation attacks. Additionally, the vulnerability results in unnecessary performance state votes being maintained for devices that should no longer require such power management attention, leading to inefficient resource utilization and potential performance degradation in systems with complex power domain hierarchies.
The fix implemented addresses this vulnerability by adding the missing pm_runtime_disable() call within the genpd_dev_pm_detach() function, ensuring proper cleanup of runtime power management state during device detachment. This remediation aligns with the established principles of power management system design and follows the security principle of least privilege by ensuring that only properly attached devices maintain active runtime power management states. The solution directly addresses the CWE-691 weakness category related to insufficient protection of code against power management attacks, while also supporting the ATT&CK framework's system and network reconnaissance techniques by preventing potential information disclosure through improper device state management. This fix ensures that power domain operations maintain consistent and predictable behavior, preventing the accumulation of stale power management references that could otherwise lead to system instability or security vulnerabilities.