CVE-2024-46744 is a vulnerability identified in the Linux kernel's handling of Squashfs symbolic links. Squashfs is a compressed read-only filesystem commonly used in embedded systems, live Linux distributions, and container images. The vulnerability arises from improper validation of the symbolic link size read from disk. Specifically, when the kernel function squashfs_read_inode() reads a corrupted symbolic link size, it assigns an abnormally large value (e.g., 3875536935) to the inode's i_size field. Subsequently, squashfs_symlink_read_folio() uses this corrupted size as a signed integer length variable. Due to integer overflow, this length becomes negative, causing a loop that should copy symbolic link data into a page to be skipped. As a result, the page remains uninitialized, leading to a use of uninitialized memory. This uninitialized memory usage can cause unpredictable behavior including potential information leakage, kernel crashes, or memory corruption. The patch for this vulnerability introduces a sanity check to ensure the symbolic link size does not exceed expected limits, preventing the overflow and uninitialized memory condition. No known exploits are currently reported in the wild, and the vulnerability was published shortly after being reserved, indicating a proactive disclosure. The vulnerability affects Linux kernel versions containing the specified commit hashes prior to patching. Given that Squashfs is widely used in various Linux distributions and embedded devices, this vulnerability has broad implications for systems relying on this filesystem.

For European organizations, the impact of CVE-2024-46744 can be significant depending on their use of Linux systems that utilize Squashfs. Many European enterprises and public sector organizations deploy Linux-based servers, network appliances, and embedded devices that may use Squashfs for firmware or container images. Exploitation could lead to kernel crashes causing denial of service, or potentially memory corruption that might be leveraged for privilege escalation or information disclosure. Critical infrastructure sectors such as telecommunications, manufacturing, and transportation that rely on embedded Linux devices are particularly at risk. Additionally, cloud service providers and data centers in Europe running Linux containers or live images with Squashfs could face service disruptions or security breaches. Although no exploits are currently known, the vulnerability's nature—uninitialized memory usage triggered by corrupted symbolic link data—could be weaponized by attackers with local access or through crafted filesystem images. This elevates the risk for organizations that allow untrusted users to mount or interact with Squashfs images. The impact on confidentiality, integrity, and availability varies but could be severe if exploited in sensitive environments.

European organizations should prioritize updating their Linux kernels to versions that include the patch for CVE-2024-46744. Specifically, applying the latest stable kernel releases or vendor-provided security updates that incorporate the symbolic link size sanity check is critical. For embedded devices and appliances, vendors should be contacted to obtain firmware updates addressing this issue. Organizations should audit their use of Squashfs images, especially those sourced externally or from untrusted origins, and restrict mounting or processing of such images to trusted administrators. Implementing strict access controls and monitoring for unusual kernel crashes or memory errors related to Squashfs can help detect exploitation attempts. Additionally, sandboxing or isolating processes that handle Squashfs images reduces the risk of privilege escalation. For containerized environments, rebuilding container images with patched kernels and verifying the integrity of Squashfs layers is recommended. Finally, organizations should maintain robust incident response plans to address potential exploitation scenarios involving kernel memory corruption.