CVE-2021-33656
First published: Tue Jan 05 2021(Updated: )
A flaw in the Linux Kernel console driver found. When setting font with malicious data by ioctl PIO_FONT, 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: <a href="https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patch">https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patch</a>
Credit: securities@openeuler.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| redhat/kernel-rt | <0:4.18.0-477.10.1.rt7.274.el8_8 | 0:4.18.0-477.10.1.rt7.274.el8_8 |
| redhat/kernel | <0:4.18.0-477.10.1.el8_8 | 0:4.18.0-477.10.1.el8_8 |
| redhat/kernel | <0:4.18.0-372.70.1.el8_6 | 0:4.18.0-372.70.1.el8_6 |
| redhat/Kernel | <5.12 | 5.12 |
| openEuler | =20.03 | |
| openEuler | =20.03-sp1 | |
| openEuler | =20.03-sp3 | |
| Linux Kernel | <5.10.127 | |
| Debian | =10.0 | |
| debian/linux | 5.10.223-1 5.10.234-1 6.1.123-1 6.1.128-1 6.12.12-1 6.12.17-1 |
Remedy
Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
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Reference Links
- https://www.cve.org/CVERecord?id=CVE-2021-33656 https://nvd.nist.gov/vuln/detail/CVE-2021-33656 https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patch
- https://bugzilla.redhat.com/show_bug.cgi?id=2108696
- https://access.redhat.com/errata/RHSA-2023:2736
- https://access.redhat.com/errata/RHSA-2023:2951
- https://access.redhat.com/errata/RHSA-2023:4789
- https://access.redhat.com/security/cve/cve-2021-33656
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patch
- https://www.openeuler.org/en/security/cve/detail.html?id=CVE-2021-33656&packageName=kernel
- http://www.openwall.com/lists/oss-security/2022/07/19/3
- https://lists.debian.org/debian-lts-announce/2022/10/msg00000.html
- https://launchpad.net/bugs/cve/CVE-2021-33656
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=2109148
- https://www.openeuler.org/en/security/cve/detail.html?id=CVE-2021-33656&packageName=kernel
- https://git.kernel.org/linus/ff2047fb755d4415ec3c70ac799889371151796d
- https://security-tracker.debian.org/tracker/CVE-2021-33656
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-33656
- https://nvd.nist.gov/vuln/detail/CVE-2021-33656
- https://ubuntu.com/security/CVE-2021-33656
Parent vulnerabilities
(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.
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