Loop Device Block Size Vulnerability in Linux Kernel by Linux Foundation

CVE-2025-38709

What is CVE-2025-38709?

A vulnerability in the Linux kernel affects loop devices, where changing the block size underneath a mounted filesystem can lead to inconsistencies. This mismatch between the loop device's block size and the superblock's recorded size creates potential instability in file system operations. The issue arises when the system attempts to perform actions that depend on a consistent block size, resulting in errors and warnings that may impact data integrity. The vulnerability is addressed by ensuring exclusive access to the loop device before making block size changes, which prevents conflicts with filesystem ownership.

References