CVE-2024-47746 is a vulnerability identified in the Linux kernel's FUSE (Filesystem in Userspace) implementation. The issue arises from improper locking behavior when the FUSE_I_CACHE_IO_MODE bit is set. Specifically, the kernel code mistakenly uses a shared lock where an exclusive lock is required. According to the vulnerability description, shared locks are not allowed when this bit is set, and using a shared lock can cause the wait operation in the function fuse_file_cached_io_open to hang indefinitely. This behavior can lead to a denial of service (DoS) condition where processes attempting to access FUSE-mounted filesystems may become stuck, potentially causing system instability or degraded performance. The vulnerability is rooted in a likely typo or logic error in the kernel source code, which has since been resolved by enforcing the use of exclusive locks under the specified condition. No known exploits are currently reported in the wild, and no CVSS score has been assigned yet. The affected versions are identified by specific commit hashes, indicating that the vulnerability affects certain recent Linux kernel versions prior to the patch. Since FUSE is widely used to allow non-privileged users to create their own filesystems, this vulnerability could impact a broad range of Linux distributions and applications relying on FUSE for filesystem operations.

For European organizations, the impact of CVE-2024-47746 primarily revolves around potential denial of service scenarios on Linux systems utilizing FUSE filesystems. Many enterprises, research institutions, and cloud providers in Europe run Linux-based infrastructure where FUSE is employed for user-space filesystems, container storage, or networked filesystems. A successful exploitation could cause processes to hang indefinitely, leading to service disruptions, degraded application performance, or system instability. This can affect critical services, especially in sectors such as finance, telecommunications, and government, where Linux servers are prevalent. While the vulnerability does not appear to allow privilege escalation or direct data compromise, the availability impact could indirectly affect confidentiality and integrity if systems become unresponsive or require rebooting. The absence of known exploits reduces immediate risk, but the widespread use of Linux and FUSE means that unpatched systems remain vulnerable to potential future attacks or accidental system hangs.

To mitigate CVE-2024-47746, European organizations should promptly apply the official Linux kernel patches that enforce exclusive locking when FUSE_I_CACHE_IO_MODE is set. Kernel updates should be prioritized on all systems running FUSE filesystems, especially those in production or critical environments. System administrators should audit their environments to identify FUSE usage and verify kernel versions against the patched commits. Additionally, monitoring for unusual process hangs or filesystem access delays can help detect exploitation attempts or impact from this vulnerability. For environments where immediate patching is not feasible, consider temporarily disabling FUSE mounts or restricting user access to FUSE filesystems to reduce exposure. Incorporating this vulnerability into vulnerability management and patching workflows will ensure timely remediation. Finally, organizations should maintain up-to-date backups and have incident response plans to handle potential denial of service incidents stemming from this issue.