CVE-2020-8647: Use After Free
A flaw was found in the Linux kernel’s virtual console resize functionality. An attacker with local access to virtual consoles can use the virtual console resizing code to gather kernel internal data structures.
Other sources
An out of bounds read vulnerability in the virtual console/virtual terminal resize functionality. An attacker with a local account can use the resize functionality to possibly leak kernel internal information to the local console which may be captured for use in a further attack to increase the reliability and successfulness of the next attack.
Reference: Kernel Bugzilla: https://bugzilla.kernel.org/showbug.cgi?id=206359 Proposed patch: https://lkml.org/lkml/2020/3/1/415
— Red Hat
There is a use-after-free vulnerability in the Linux kernel through 5.5.2 in the vcdoresize function in drivers/tty/vt/vt.c.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 0:3.10.0-1160.rt56.1131.el7 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:3.10.0-1160.el7 - Upgrade
Upgrade
redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 0:4.18.0-240.rt7.54.el8 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:4.18.0-240.el8 - Upgrade
Upgrade
redhat/kernel-rtto a version that resolves this vulnerability.Fixed in 0:4.18.0-193.80.1.rt13.130.el8_2 - Upgrade
Upgrade
redhat/kernelto a version that resolves this vulnerability.Fixed in 0:4.18.0-193.80.1.el8_2 - Upgrade
Upgrade
debian/linuxto a version that resolves this vulnerability.Fixed in 4.19.249-2Fixed in 4.19.289-2Fixed in 5.10.197-1Fixed in 5.10.191-1Fixed in 6.1.66-1Fixed in 6.1.69-1Fixed in 6.5.13-1Fixed in 6.6.9-1 - Upgrade
Upgrade
linux kernelto a version that resolves this vulnerability.Patch 206359 - Compensating control
Prevent users from logging into the local virtual console (deny local console login). Use the referenced Red Hat instructions on disabling local login and the pam_console section to deny users logging into the console.
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2020-8647?
The severity of CVE-2020-8647 is assessed as medium with a CVSS score of 6.1.
How do I fix CVE-2020-8647?
To fix CVE-2020-8647, update to the latest kernel version provided by your Linux distribution.
Can CVE-2020-8647 be exploited remotely?
No, CVE-2020-8647 requires local access to virtual consoles to be exploited.
What types of systems are affected by CVE-2020-8647?
CVE-2020-8647 affects various Linux distributions including Red Hat, Debian, Google Android, and openSUSE Leap.
What kind of vulnerability is CVE-2020-8647?
CVE-2020-8647 is an out of bounds read vulnerability leading to potential information leakage from the Linux kernel.