CVE-2026-64023 in Linux
Summary
by MITRE • 07/19/2026
In the Linux kernel, the following vulnerability has been resolved:
gpio: aggregator: fix a potential use-after-free
On error we free aggr->lookups->dev_id before removing the entry from the lookup table. If a concurrent thread calls gpiod_find() before we remove the entry, it could iterate over the list and call gpiod_match_lookup_table() which unconditionally dereferences dev_id when calling strcmp(). Reverse the order of cleanup.
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Analysis
by VulDB Data Team • 07/19/2026
This vulnerability represents a critical use-after-free condition in the Linux kernel's GPIO aggregator subsystem that arises from improper resource management during error handling scenarios. The flaw occurs within the gpio_aggregator subsystem where the kernel attempts to clean up resources while processing errors, creating a race condition that can lead to memory corruption and potential privilege escalation. When an error condition is encountered during GPIO lookup table operations, the system first frees the aggr->lookups->dev_id memory region before removing the corresponding entry from the lookup table structure. This sequence creates a temporal window where concurrent threads executing gpiod_find() calls can access the already-freed memory, resulting in undefined behavior that may manifest as system crashes or exploitable conditions.
The technical implementation of this vulnerability stems from a fundamental flaw in the cleanup ordering within the GPIO aggregation framework. The subsystem maintains a lookup table structure that maps device identifiers to GPIO configurations, and during error conditions the kernel's resource management logic executes operations in an incorrect sequence. When gpiod_find() is invoked by concurrent threads, it iterates through the active lookup entries and calls gpiod_match_lookup_table() function which unconditionally dereferences the dev_id field without proper validation. This direct memory access to freed data violates standard memory safety principles and creates a classic use-after-free scenario that aligns with CWE-416, specifically addressing the improper management of memory resources after they have been freed.
The operational impact of this vulnerability extends beyond simple system instability to potentially enable privilege escalation attacks within kernel space. Attackers could exploit this race condition by carefully orchestrating concurrent access patterns to trigger the use-after-free condition, potentially leading to arbitrary code execution with kernel privileges. The vulnerability affects systems running Linux kernels that implement GPIO aggregator functionality, particularly those utilizing device tree configurations or complex GPIO mapping scenarios where multiple threads might simultaneously access GPIO lookup operations. This type of vulnerability is categorized under ATT&CK technique T1068, which deals with exploit for privilege escalation, and demonstrates how memory corruption flaws in kernel subsystems can provide attackers with elevated system access.
Mitigation strategies for this vulnerability require immediate kernel updates from vendors who have addressed the issue through proper resource management fixes. The recommended solution involves reversing the cleanup order to ensure that entries are removed from lookup tables before freeing associated memory regions, thereby eliminating the race condition window. System administrators should prioritize applying security patches from their Linux distribution providers and monitor for any related kernel updates that address similar memory management issues in GPIO subsystems. Additionally, implementing proper kernel memory debugging tools such as kmemcheck or enabling CONFIG_DEBUG_LIST kernel configuration options can help detect similar race conditions in development environments. Organizations should also consider monitoring for unusual GPIO-related system calls and implement intrusion detection systems that can identify potential exploitation attempts targeting kernel memory corruption vulnerabilities.