Linux Kernel VMA Unmapping Error in Stacked Driver Hooks

CVE-2026-53373 is a high-severity vulnerability in the Linux kernel's memory management subsystem, specifically affecting how virtual memory areas (VMAs) are handled during mmap operations in stacked drivers. Stacked drivers—such as overlayfs and shared memory implementations—can invoke mmap hooks of other drivers, creating complex call chains. The vulnerability occurs when mmap_prepare() is called from within an existing mmap() hook; improper error handling attempts to unmap VMAs that shouldn't be unmapped, potentially leading to memory corruption, kernel panics, or privilege escalation. This affects Linux systems using stacked filesystem or memory-mapping drivers, particularly in containerized environments and cloud infrastructure where overlayfs is commonly deployed.

While CVE-2026-53373 currently has no mapped MITRE ATT&CK techniques or CWE classification, Casky's extended reasoning capabilities would detect attack patterns associated with kernel memory manipulation and privilege escalation chains. Practitioners using Casky would observe suspicious memory access patterns, abnormal VMA state transitions, and kernel execution anomalies that correlate with memory management exploits. The platform's 754 mapped security skills would flag kernel-level defensive bypass attempts and post-exploitation behaviors that typically follow successful memory corruption attacks. Detection would focus on monitoring mmap() syscall chains, identifying stacked driver interactions, and correlating kernel warnings with process privilege elevation—enabling security teams to identify exploitation attempts before successful compromise.