CVE-2021-33656

Name: CVE-2021-33656
Creator: NVD / NIST
Published: 2022-07-18T15:15:08.043+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.8/10EPSS 0.54%

Last modified Jun 17, 2026

CVE-2021-33656 is a medium-severity vulnerability rated 6.8/10 on the CVSS scale. When setting font with malicous data by ioctl cmd PIO_FONT,kernel will write memory out of bounds.. EPSS estimates a 0.54% chance of exploitation in the next 30 days.

Description

When setting font with malicous data by ioctl cmd PIO_FONT,kernel will write memory out of bounds.

Metrics

CVSS 3.1

6.8/10

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS Probability

0.54%

41.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Openatom	Openeuler	20.03
Linux	Linux Kernel	< 5.10.127
Debian	Debian Linux	10.0

References

http://www.openwall.com/lists/oss-security/2022/07/19/3Mailing List, Patch, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patchPatch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/10/msg00000.htmlMailing List, Third Party Advisory
https://www.openeuler.org/en/security/cve/detail.html?id=CVE-2021-33656&packageName=kernelThird Party Advisory
http://www.openwall.com/lists/oss-security/2022/07/19/3Mailing List, Patch, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patchPatch, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2022/10/msg00000.htmlMailing List, Third Party Advisory
https://www.openeuler.org/en/security/cve/detail.html?id=CVE-2021-33656&packageName=kernelThird Party Advisory

Timeline

Published: Jul 18, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-33656?

When setting font with malicous data by ioctl cmd PIO_FONT,kernel will write memory out of bounds.

How severe is CVE-2021-33656?

CVE-2021-33656 has a CVSS score of 6.8/10 (MEDIUM severity). The EPSS model estimates a 0.54% probability of exploitation in the next 30 days.

How do I fix CVE-2021-33656?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-33656?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST