CVE-2021-33656: Medium severity openeuler vulnerability
A flaw in the Linux Kernel console driver found. When setting font with malicious data by ioctl PIOFONT, kernel will write memory out of bounds. To trigger the vulnerability user need to have access to console driver like if text mode being used through a generic VGA standard display.
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patch
Other sources
An out-of-bounds write flaw was found in the Linux kernel’s console driver functionality in the way a user triggers the ioctl PIOFONT with malicious data. This flaw allows a local user to crash or potentially escalate their privileges on the system.
When setting font with malicous data by ioctl cmd PIOFONT,kernel will write memory out of bounds.
Affected Software
Remediation
Information
Patch Available
Event History
Parent advisories
This vulnerability appears in the following advisories.
Frequently Asked Questions
What is the severity of CVE-2021-33656?
CVE-2021-33656 has a high severity rating due to the potential for memory corruption and denial of service when exploited.
How do I fix CVE-2021-33656?
To fix CVE-2021-33656, ensure that your kernel package is updated to a version that includes the patch, specifically at least 0:4.18.0-477.10.1.rt7.274.el8_8 for Red Hat or corresponding updates for other affected distributions.
Who is affected by CVE-2021-33656?
CVE-2021-33656 affects multiple Linux kernel versions, particularly those used in Red Hat and Huawei OpenEuler systems.
What can happen if CVE-2021-33656 is exploited?
Exploitation of CVE-2021-33656 could result in a kernel crash or the execution of arbitrary code leading to a system compromise.
How is CVE-2021-33656 triggered?
CVE-2021-33656 is triggered when a user with access to the console driver sends malicious data via the ioctl PIO_FONT command.