CVE-2025-22076 is a vulnerability identified in the Linux kernel's exFAT filesystem driver. The issue arises from missing shutdown checks in critical file operation functions such as read_iter, write_iter, splice_read, and mmap. Specifically, after a device with dirty data is deleted, the system could still read data without returning an error, indicating that the kernel did not properly verify whether the filesystem was shut down or unmounted before allowing access. This flaw was detected during the xfstests generic/730 test, which failed because it could read data from a device that should have been inaccessible. The vulnerability implies that the kernel might allow read or write operations on a filesystem that is in an inconsistent or unclean state, potentially leading to data corruption or unauthorized data access. The patch adds necessary shutdown checks to these functions to ensure that no operations occur on a device that has been logically removed or shut down. Although no known exploits are currently reported in the wild, the vulnerability affects the Linux kernel's exFAT implementation, which is widely used for interoperability with external storage devices formatted with exFAT. The affected versions correspond to specific kernel commits prior to the fix published on April 16, 2025.

For European organizations, this vulnerability could have several impacts. Many enterprises and public sector organizations in Europe rely on Linux-based systems for servers, workstations, and embedded devices. The exFAT filesystem is commonly used for removable media such as USB drives and SD cards, which are frequently used for data transfer and backup. The missing shutdown checks could allow unauthorized read or write operations on devices that have been logically removed or are in an inconsistent state, potentially leading to data leakage, data corruption, or system instability. This is particularly concerning in environments where removable media are used to transfer sensitive information or where data integrity is critical, such as in finance, healthcare, and government sectors. Although exploitation requires local access and likely some user interaction (e.g., mounting or accessing a device), the risk of data integrity compromise and unauthorized data exposure remains significant. Additionally, the vulnerability could be leveraged as part of a broader attack chain to escalate privileges or disrupt system operations.

European organizations should promptly apply the Linux kernel patches that address CVE-2025-22076 to ensure shutdown checks are enforced in the exFAT filesystem driver. System administrators should audit their Linux systems to identify those running affected kernel versions and prioritize updates. Where immediate patching is not feasible, organizations should restrict the use of removable media formatted with exFAT or enforce strict device usage policies, including disabling auto-mounting of external devices and monitoring filesystem mount/unmount events. Implementing endpoint security solutions that detect anomalous filesystem activity can help identify exploitation attempts. Additionally, organizations should educate users about the risks of using untrusted removable media and enforce least privilege principles to limit local user capabilities. Regular backups and integrity checks of critical data stored on removable media will also mitigate potential data corruption impacts.