CVE-2026-68178 misc: nsm: pin the module while the device is open
An attacker with an open file descriptor can trigger a use-after-free by unloading the NSM kernel module, potentially leading to code execution or privilege escalation.
- 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-2026-68178?
CVE-2026-68178 is a high-severity use after free vulnerability in Linux, published on 10 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:
misc: nsm: pin the module while the device is open
misc_open() installs a misc driver's file operations with fops_get(), which pins file_operations::owner before replacing the file's f_op. The NSM misc device leaves nsm_dev_fops.owner unset, so opening /dev/nsm does not take a module reference on the nsm driver.
If the driver is built as a module, an open file descriptor can therefore survive rmmod of the module that provides its ioctl callbacks. A later ioctl through that descriptor can call into unloaded module text.
Set nsm_dev_fops.owner to THIS_MODULE so the misc core holds the module while any /dev/nsm file descriptor is open, matching the lifetime expectation for the installed file operations.
Weakness: CWE-416
Which versions are affected by CVE-2026-68178?
How do I fix CVE-2026-68178?
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-2026-68178 being exploited?
There is no known exploitation of CVE-2026-68178 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-68178, DEBIAN-CVE-2026-68178, GHSA-785r-497w-84xv, UBUNTU-CVE-2026-68178.