CVE-2019-20794

Severity: medium (CVSS 4.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2020-05-09 · updated 2026-10-08
Weakness: CWE-772

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.

Affected products

Linux kernel: from 4.18 through 5.6.11

References

http://www.openwall.com/lists/oss-security/2020/08/24/1
https://github.com/sargun/fuse-example
https://security.netapp.com/advisory/ntap-20200608-0001/
https://sourceforge.net/p/fuse/mailman/message/36598753/
http://www.openwall.com/lists/oss-security/2020/08/24/1
https://github.com/sargun/fuse-example
https://security.netapp.com/advisory/ntap-20200608-0001/
https://sourceforge.net/p/fuse/mailman/message/36598753/

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