UBUNTU-CVE-2026-97949: Use After Free

In the Linux kernel, the following vulnerability has been resolved: configfs: unhash the dentry before dropping the item in rmdir configfsgetconfigitem() treats a hashed dentry as proof that sd->selement is a live configitem. configfsrmdir() breaks that: simplermdir() leaves the dentry hashed, the last reference to the item is dropped right after, and the dentry is only unhashed by ddelete() once ->rmdir() has returned. configfssymlink() resolves its target holding no lock on it, so gettarget() can land in that window: BUG: KASAN: slab-use-after-free in configitemget+0x26/0x90 gettarget fs/configfs/symlink.c:128 [inline] configfssymlink+0x4ab/0x1030 fs/configfs/symlink.c:185 Unhash in configfsremovedir(), while the item is still guaranteed to be there. A reference obtained just before that stays harmless, as createlink() rechecks CONFIGFSUSETDROPPING, already set by configfsdetachprep(). Both configfsunregistersubsystem() paths ddrop() after detaching, so this only makes rmdir match them.