CVE-2020-10781

Published: 18 June 2020

A flaw was found in the Linux Kernel before 5.8-rc6 in the ZRAM kernel module, where a user with a local account and the ability to read the /sys/class/zram-control/hot_add file can create ZRAM device nodes in the /dev/ directory. This read allocates kernel memory and is not accounted for a user that triggers the creation of that ZRAM device. With this vulnerability, continually reading the device may consume a large amount of system memory and cause the Out-of-Memory (OOM) killer to activate and terminate random userspace processes, possibly making the system inoperable.

From the Ubuntu security team

Luca Bruno discovered that the zram module in the Linux kernel did not properly restrict unprivileged users from accessing the hot_add sysfs file. A local attacker could use this to cause a denial of service (memory exhaustion).

Priority

Low

CVSS 3 base score: 5.5

Status

Notes

zram module is not loaded by default, but is enabled.

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-10781
• https://www.openwall.com/lists/oss-security/2020/06/18/1
• https://lore.kernel.org/linux-block/20200617103412.GA2027053@kroah.com/
• https://ubuntu.com/security/notices/USN-4483-1
• https://ubuntu.com/security/notices/USN-4485-1
• NVD
• Launchpad
• Debian

Bugs

• https://bugzilla.redhat.com/show_bug.cgi?id=1847832