Out-of-Bounds Read Vulnerability in Linux Kernel by Linux Foundation

CVE-2025-39840

What is CVE-2025-39840?

A vulnerability has been identified in the Linux kernel where an out-of-bounds read occurs during the audit comparison of directory names. Specifically, this issue arises when a filesystem notification event (fsnotify) is triggered for a single-character name directly under the root directory, such as creating '/a'. The underlying cause is a flaw in the audit_compare_dname_path() function, which fails to adequately check the length of the path, allowing the code to dereference invalid memory. To address this vulnerability, a condition has been implemented in the while loop to ensure that path length is greater than zero, thus preventing such unsafe memory access.

References