CVE-2022-50751 configfs: fix possible memory leak in configfs_create_dir()
A memory leak in the Linux kernel configfs subsystem can lead to resource exhaustion and denial of service.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-50751?
CVE-2022-50751 is a memory corruption vulnerability in Linux, published on 24 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
configfs: fix possible memory leak in configfs_create_dir()
kmemleak reported memory leaks in configfs_create_dir():
unreferenced object 0xffff888009f6af00 (size 192): comm "modprobe", pid 3777, jiffies 4295537735 (age 233.784s) backtrace: kmem_cache_alloc (mm/slub.c:3250 mm/slub.c:3256 mm/slub.c:3263 mm/slub.c:3273) new_fragment (./include/linux/slab.h:600 fs/configfs/dir.c:163) configfs_register_subsystem (fs/configfs/dir.c:1857) basic_write (drivers/hwtracing/stm/p_basic.c:14) stm_p_basic do_one_initcall (init/main.c:1296) do_init_module (kernel/module/main.c:2455) ...
unreferenced object 0xffff888003ba7180 (size 96): comm "modprobe", pid 3777, jiffies 4295537735 (age 233.784s) backtrace: kmem_cache_alloc (mm/slub.c:3250 mm/slub.c:3256 mm/slub.c:3263 mm/slub.c:3273) configfs_new_dirent (./include/linux/slab.h:723 fs/configfs/dir.c:194) configfs_make_dirent (fs/configfs/dir.c:248) configfs_create_dir (fs/configfs/dir.c:296) configfs_attach_group.isra.28 (fs/configfs/dir.c:816 fs/configfs/dir.c:852) configfs_register_subsystem (fs/configfs/dir.c:1881) basic_write (drivers/hwtracing/stm/p_basic.c:14) stm_p_basic do_one_initcall (init/main.c:1296) do_init_module (kernel/module/main.c:2455) ...
This is because the refcount is not correct in configfs_make_dirent(). For normal stage, the refcount is changing as:
configfs_register_subsystem() configfs_create_dir() configfs_make_dirent() configfs_new_dirent() # set s_count = 1 dentry->d_fsdata = configfs_get(sd); # s_count = 2 ... configfs_unregister_subsystem() configfs_remove_dir() remove_dir() configfs_remove_dirent() # s_count = 1 dput() ... *dentry_unlink_inode()* configfs_d_iput() # s_count = 0, release
However, if we failed in configfs_create():
configfs_register_subsystem() configfs_create_dir() configfs_make_dirent() # s_count = 2 ... configfs_create() # fail ->out_remove: configfs_remove_dirent(dentry) configfs_put(sd) # s_count = 1 return PTR_ERR(inode);
There is no inode in the error path, so the configfs_d_iput() is lost and makes sd and fragment memory leaked.
To fix this, when we failed in configfs_create(), manually call configfs_put(sd) to keep the refcount correct.
Which versions are affected by CVE-2022-50751?
How do I fix CVE-2022-50751?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2022-50751 being exploited?
There is no known exploitation of CVE-2022-50751 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2022-50751, GHSA-7px2-rh6v-wcpc, UBUNTU-CVE-2022-50751.