CVE-2026-74359 configfs_lookup(): don't leave ->s_dentry dangling on failure
A use-after-free vulnerability in the Linux kernel's configfs_lookup function allows attackers to potentially execute code or escalate privileges via a dangling pointer dereference.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74359?
CVE-2026-74359 is a high-severity use after free vulnerability in Linux, published on 15 Aug 2026. 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_lookup(): don't leave ->s_dentry dangling on failure
Normally ->s_dentry is cleared when dentry it's pointing to becomes negative (on eviction, realistically). However, that only happens if dentry gets to be positive in the first place; in case of inode allocation failure dentry never becomes positive, so ->d_iput() is not called at all.
We do part of what normally would've been done by configfs_d_iput() (dropping the reference to configfs_dirent) manually, but we do not clear ->s_dentry there. Sloppy as it is, it does not matter in case of configfs_create_{dir,link}() - there configfs_dirent does not survive dropping the sole reference to it.
However, for configfs_lookup() it *does* survive, with a dangling pointer to soon to be freed dentry sitting it its ->s_dentry.
Subsequent getdents(2) in that directory will end up dereferencing that pointer in order to pick the inode number. Use after free...
This is the minimal fix; the right approach is to set the linkage between dentry and configfs_dirent only after we know that we have an inode, but that takes more surgery and the bug had been there since 2006, so...
Which versions are affected by CVE-2026-74359?
How do I fix CVE-2026-74359?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-74359 being exploited?
There is no known exploitation of CVE-2026-74359 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-74359, DEBIAN-CVE-2026-74359, GHSA-w2rw-4pc9-v672, UBUNTU-CVE-2026-74359.