CVE-2026-98388 exec: do_close_on_exec() before taking exec_update_lock
A local attacker can cause a system deadlock or hang by exploiting a race condition involving filesystem operations during process execution.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98388?
CVE-2026-98388 is a denial of service vulnerability in Linux, published on 14 Oct 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:
exec: do_close_on_exec() before taking exec_update_lock
do_close_on_exec() currently happens while holding the exec_update_lock, which is used in a lot of places that access process state to synchronize access checks. I recently added another such use of exec_update_lock, causing a regression.
do_close_on_exec() can block waiting for a reply from a filesystem. That means a hung filesystem can block codepaths that use exec_update_lock; and it also means that a FUSE filesystem which attempts to inspect the calling process can deadlock.
To avoid such problems, move do_close_on_exec() before the exec_update_lock is taken, but after the FD table has been copied if necessary.
I have looked through all the calls between the old and new position of the do_close_on_exec() call; there seems to be no file descriptor table access in between.
Which versions are affected by CVE-2026-98388?
How do I fix CVE-2026-98388?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-98388 being exploited?
There is no known exploitation of CVE-2026-98388 in the wild and no public exploit code.
Sources
Also known as AZL-108174, BELL-CVE-2026-98388, DEBIAN-CVE-2026-98388, GHSA-chvx-fr8p-v654, UBUNTU-CVE-2026-98388.