What’s Vulnerable › Vulnerabilities
CVE-2021-33656
- Severity: medium (CVSS 6.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.6% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2022-07-18 · updated 2026-10-08
- Weakness: CWE-787
Description
When setting font with malicous data by ioctl cmd PIO_FONT,kernel will write memory out of bounds.
Affected products
- Debian Linux: 10.0
- Linux kernel: before 5.10.127 — fixed in 5.10.127
- Openatom Openeuler: 20.03, 20.03-sp1, 20.03-sp3
How to fix
Upgrade to a fixed version: Linux kernel 5.10.127. Check the vendor advisory for mitigations.
References
- http://www.openwall.com/lists/oss-security/2022/07/19/3
- 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://lists.debian.org/debian-lts-announce/2022/10/msg00000.html
- 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://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patch
- https://lists.debian.org/debian-lts-announce/2022/10/msg00000.html
- https://www.openeuler.org/en/security/cve/detail.html?id=CVE-2021-33656&packageName=kernel
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