CVE-2025-21887

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description The issue is caused by a use-after-free error in the ovl dentry update reval function. This error occurs because dput(upper) is called before ovl dentry update reval(), while upper->d flags is still accessed in ovl dentry remote(). To fix this, dput(upper) is moved after its last use. The problem was identified by KASAN, which reported a slab-use-after-free error in ovl dentry remote and ovl dentry update reval.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.