CVE-2024-53111 is a vulnerability identified in the Linux kernel's memory management subsystem, specifically within the mm/mremap function responsible for remapping virtual memory areas. The flaw occurs on 32-bit platforms due to an integer overflow in the calculation involving the length and old address parameters in move_page_tables(). The vulnerability arises because the expression `len + old_addr < old_end` can yield a false negative if the addition wraps around the 32-bit address space, causing the kernel to incorrectly assume that page table entries (PTEs) have been successfully moved when they have not. As a result, mremap() aborts the operation without restoring the original PTEs before unmapping the new virtual memory area (VMA). This leads to the loss of anonymous private pages' contents, effectively zeroing out the memory region that userspace attempted to remap. The issue is demonstrated by a test program that maps a large anonymous memory region, writes a value, and then attempts to remap it to a different address. Without the patch, mremap() fails and the original data is lost (zeroed), whereas with the patch, mremap() succeeds and data integrity is preserved. The fix involves rearranging the comparison to avoid the wraparound problem, ensuring the kernel correctly tracks the movement of page tables. This vulnerability affects 32-bit Linux kernels and is particularly relevant for applications relying on mremap() for memory management of private anonymous regions. Although no known exploits are reported in the wild, the bug can cause data loss and application errors due to unexpected zeroing of memory regions during remapping operations.

For European organizations, the impact of CVE-2024-53111 primarily concerns systems running 32-bit Linux kernels that utilize the mremap() syscall for memory management, especially in environments where large anonymous private memory regions are remapped. The vulnerability can lead to silent data loss within affected processes, potentially causing application crashes, data corruption, or unexpected behavior in memory-intensive applications. This could affect legacy systems, embedded devices, or specialized industrial and network equipment still operating on 32-bit Linux kernels. Although the vulnerability does not directly enable privilege escalation or remote code execution, the loss of data integrity can disrupt critical services, particularly in sectors such as manufacturing, telecommunications, and public infrastructure where embedded Linux devices are common. Additionally, debugging and recovery efforts may increase operational costs and downtime. Since the issue is limited to 32-bit platforms, the impact on modern 64-bit Linux deployments is minimal. However, organizations with mixed environments or legacy systems should assess their exposure carefully.

1. Immediate application of the official Linux kernel patch that corrects the address wraparound check in move_page_tables() is the most effective mitigation. Organizations should prioritize updating 32-bit Linux kernel versions to the fixed release. 2. For systems where kernel upgrades are not immediately feasible, consider auditing applications and services that rely on mremap() for large anonymous private memory remapping and evaluate if they can be reconfigured to avoid triggering this code path. 3. Implement monitoring to detect abnormal application crashes or memory corruption symptoms that could indicate exploitation of this bug. 4. For embedded or specialized devices, coordinate with hardware and software vendors to obtain patched firmware or kernel updates. 5. Review and limit the use of 32-bit Linux systems where possible, migrating to 64-bit platforms to reduce exposure to this and similar legacy vulnerabilities. 6. Conduct thorough testing of memory management operations post-patch to ensure system stability and data integrity. 7. Maintain robust backup and recovery procedures to mitigate data loss risks from unexpected application failures.