CVE-2019-20794 Denial of service in n/a
An attacker can cause a system hang and resource exhaustion by terminating a FUSE filesystem process within a user namespace.
- 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-2019-20794?
CVE-2019-20794 is a medium-severity denial of service vulnerability in Linux kernel, published on 9 May 2020. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
An issue was discovered in the Linux kernel 4.18 through 5.6.11 when unprivileged user namespaces are allowed. A user can create their own PID namespace, and mount a FUSE filesystem. Upon interaction with this FUSE filesystem, if the userspace component is terminated via a kill of the PID namespace's pid 1, it will result in a hung task, and resources being permanently locked up until system reboot. This can result in resource exhaustion.
Weakness: CWE-772
Which versions are affected by CVE-2019-20794?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2019-20794?
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-2019-20794 being exploited?
There is no known exploitation of CVE-2019-20794 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as DEBIAN-CVE-2019-20794, GHSA-j4w8-rj66-g2q9, ROOT-OS-DEBIAN-11-CVE-2019-20794, ROOT-OS-DEBIAN-12-CVE-2019-20794, ROOT-OS-DEBIAN-13-CVE-2019-20794, UBUNTU-CVE-2019-20794.