CVE-2026-63798 in Linux
Summary
by MITRE • 07/19/2026
In the Linux kernel, the following vulnerability has been resolved:
irqchip/imgpdc: Fix resource leak, add missing chained handler cleanup on remove
The driver allocates domain generic chips using irq_alloc_domain_generic_chips() during probe and sets up chained handlers using irq_set_chained_handler_and_data(). However, on driver removal, the generic chips are not freed and the chained handlers are not removed.
The generic chips remain on the global gc_list and may later be accessed by generic interrupt chip suspend, resume, or shutdown callbacks after the driver has been removed, potentially resulting in a use-after-free and kernel crash.
The chained handlers that were installed in probe for peripheral and syswake interrupts are also left dangling, which can lead to spurious interrupts accessing freed memory.
Fix these issues by:
- Setting IRQ_DOMAIN_FLAG_DESTROY_GC flag in domain->flags, so the core code automatically removes generic chips when irq_domain_remove() is called
- Clearing all chained handlers with NULL in pdc_intc_remove()
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Analysis
by VulDB Data Team • 07/19/2026
This vulnerability exists within the linux kernel's interrupt controller driver for the imgpdc device where improper resource management leads to critical memory safety issues. The problem stems from the irqchip/imgpdc driver which allocates domain generic chips using irq_alloc_domain_generic_chips() during the probe phase and establishes chained handlers through irq_set_chained_handler_and_data(). However, during driver removal, the system fails to properly clean up these allocated resources, creating persistent references that can cause severe system instability. The core issue manifests when generic chips remain accessible on the global gc_list even after the driver has been unloaded, potentially allowing access to freed memory locations during subsequent interrupt chip operations such as suspend, resume, or shutdown callbacks.
The technical flaw represents a classic use-after-free vulnerability pattern that aligns with CWE-416 and CWE-787 categories, where resources are accessed after they have been freed from memory. When the driver is removed, the generic chips are not properly deallocated through irq_domain_remove() which should automatically clean up the allocated resources when the IRQ_DOMAIN_FLAG_DESTROY_GC flag is set in the domain flags. This oversight creates a dangerous situation where memory that was previously allocated for interrupt handling becomes accessible to kernel subsystems that might attempt to use it after the driver has been removed, leading to unpredictable behavior and potential system crashes.
The operational impact of this vulnerability extends beyond simple resource leaks to encompass complete system stability threats. The dangling chained handlers that remain installed for peripheral and syswake interrupts can generate spurious interrupts that attempt to access freed memory addresses, causing kernel panics or system hangs. This represents a significant security concern as it could potentially be exploited by malicious actors to cause denial of service attacks or in extreme cases, achieve privilege escalation through controlled memory corruption. The vulnerability affects systems running linux kernels where the imgpdc driver is present and actively used for interrupt handling.
The fix implemented addresses both aspects of the resource management failure by setting the IRQ_DOMAIN_FLAG_DESTROY_GC flag in the domain flags during initialization, which ensures that when irq_domain_remove() is called during driver removal, the core kernel code automatically handles the cleanup of generic chips. Additionally, the pdc_intc_remove() function now explicitly clears all chained handlers with NULL values to prevent any lingering references to freed memory locations. This solution follows established best practices for kernel driver development and aligns with the ATT&CK framework's defense evasion techniques by ensuring proper resource cleanup and preventing memory corruption vulnerabilities that could be exploited for privilege escalation or system compromise. The fix ensures complete isolation of interrupt handling resources during driver lifecycle management, preventing access to freed memory and maintaining kernel stability throughout all operational phases.