CVE-2025-40049

A flaw was found in the Linux kernel's Squashfs filesystem driver. In squashfs_get_parent(), when open_by_handle_at() is called with a file handle containing an inode number of a symbolic link (rather than a directory), the function accesses the uninitialized parent member field. Non-directory inodes in Squashfs do not have a parent value, leading to an uninitialized value access. This could result in unpredictable behavior or information disclosure from kernel memory. A local user with the ability to mount Squashfs filesystems or use file handle operations could trigger this condition.

This vulnerability requires local access and the ability to perform file handle operations on Squashfs filesystems. The impact is primarily information disclosure of uninitialized kernel memory or potential denial of service.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent the squashfs module from being loaded if Squashfs filesystem support is not required. See https://access.redhat.com/solutions/41278 for instructions on how to blacklist a kernel module.