CVE-2024-53235: 
Linux Debian vulnerability analysis and mitigation

In the Linux kernel, a vulnerability (CVE-2024-53235) was discovered affecting file-backed mounts over FUSE. The issue was reported by syzbot and involves a null pointer dereference in the fusereadargs_fill function. This vulnerability affects Linux kernel versions from 6.12 up to (excluding) 6.12.2. The issue was discovered on December 27, 2024, and has been assigned a CVSS v3.1 base score of 5.5 (Medium) (NVD).

The vulnerability stems from improper handling of file pointers during read I/O operations in network filesystems and FUSE. The issue manifests in the call stack through fusereadfolio, filemapreadfolio, and ultimately in erofs_bread function. Unlike most filesystems, network filesystems and FUSE require valid file pointers for their read I/O operations. The vulnerability was introduced by commit fb176750266a ("erofs: add file-backed mount support") (Kernel Patch).

When exploited, this vulnerability can lead to a null pointer dereference in the kernel, potentially causing system crashes or denial of service conditions. The vulnerability has been rated with a CVSS v3.1 base score of 5.5, indicating medium severity with local access required and potential impact on system availability (NVD).

The vulnerability has been fixed in Linux kernel version 6.12.2. System administrators are advised to upgrade to this version or later. The fix involves properly handling file pointers in the erofs filesystem implementation, particularly for file-backed mounts over FUSE (Kernel Patch).