CVE-2025-38321

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

smb: Log an error when close_all_cached_dirs fails

Under low-memory conditions, close_all_cached_dirs() can't move the

dentries to a separate list to dput() them once the locks are dropped.

This will result in a "Dentry still in use" error, so add an error

message that makes it clear this is what happened:

[ 495.281119] CIFS: VFS: \\otters.example.com\share Out of memory while dropping dentries

[ 495.281595] ------------[ cut here ]------------

[ 495.281887] BUG: Dentry ffff888115531138{i=78,n=/} still in use (2) [unmount of cifs cifs]

[ 495.282391] WARNING: CPU: 1 PID: 2329 at fs/dcache.c:1536 umount_check+0xc8/0xf0

Also, bail out of looping through all tcons as soon as a single

allocation fails, since we're already in trouble, and kmalloc() attempts

for subseqeuent tcons are likely to fail just like the first one did.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References