Marek Gresko

**Name of the Vulnerable Software and Affected Versions** Linux kernel (affected versions not specified) **Description** The issue allows the root user on an NFS client to change the security labels on files on an NFS filesystem that is exported with root squashing enabled. This is due to insufficient permission checks in the `nfsd setattr()` function, which does not perform all the same permission checks as `security inode setxattr()` and its related LSM hooks. The solution involves replacing the call to ` vfs setxattr noperm()` with a call to ` vfs setxattr locked()`, which fixes the issue and also causes nfsd to recall conflicting delegations on a file when a client tries to change its security label. **Recommendations** At the moment, there is no information about a newer version that contains a fix for this vulnerability.