CVE-2021-33656
When setting font with malicous data by ioctl cmd PIO_FONT,kernel will write memory out of bounds.
02 Description
When setting font with malicous data by ioctl cmd PIO_FONT,kernel will write memory out of bounds.
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.
- EPSS probability
- 0.61% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 48.6% of scored records. A rank, not a probability.
- NVD base score
- 6.8 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-10-08.
- Red Hat severity
- Moderate. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2022-07-18 14:44Z4 YR AGO
- Last updated
- 2026-10-08 21:14Z20 DAYS AGO
- Reserved
- 2021-05-28
- Assigning CNA
- openEuler
- Record state
- PUBLISHED
- Severity
- Not rated by the issuing CNA
- CNA CVSS vector
- Not published by the issuing CNA
- Weaknesses
- CWE-787Out-of-bounds WriteBase
- Data version
- 5.2
- Document digest
- ede33cde9acbd677fbe406ad54f72e1238760d66931f74f28957ca14f9f8f842
05 Affected products
06 References
- git.kernel.orghttps://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patch
- www.openeuler.orghttps://www.openeuler.org/en/security/cve/detail.html?id=CVE-2021-33656&packageName=kernel
- www.openwall.com[oss-security] 20220719 CVE-2021-33656: Linux kernel: When setting font with malicous data by ioctl cmd PIO_FONT,kernel will write memory out of bounds.(<5.10.127)http://www.openwall.com/lists/oss-security/2022/07/19/3
- lists.debian.org[debian-lts-announce] 20221002 [SECURITY] [DLA 3131-1] linux security updatehttps://lists.debian.org/debian-lts-announce/2022/10/msg00000.html
07 Fixed in
AlmaLinux 8
- bpftool Fixed in 4.18.0-477.10.1.el8_8
- kernel Fixed in 4.18.0-477.10.1.el8_8
- kernel-abi-stablelists Fixed in 4.18.0-477.10.1.el8_8
- kernel-core Fixed in 4.18.0-477.10.1.el8_8
- kernel-cross-headers Fixed in 4.18.0-477.10.1.el8_8
- kernel-debug Fixed in 4.18.0-477.10.1.el8_8
- kernel-debug-core Fixed in 4.18.0-477.10.1.el8_8
- kernel-debug-devel Fixed in 4.18.0-477.10.1.el8_8
- kernel-debug-modules Fixed in 4.18.0-477.10.1.el8_8
- kernel-debug-modules-extra Fixed in 4.18.0-477.10.1.el8_8
- kernel-devel Fixed in 4.18.0-477.10.1.el8_8
- kernel-doc Fixed in 4.18.0-477.10.1.el8_8
- kernel-modules Fixed in 4.18.0-477.10.1.el8_8
- kernel-modules-extra Fixed in 4.18.0-477.10.1.el8_8
- kernel-rt Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-core Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug-core Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug-devel Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug-kvm Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug-modules Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug-modules-extra Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-devel Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-kvm Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-modules Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-modules-extra Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-tools Fixed in 4.18.0-477.10.1.el8_8
- kernel-tools-libs Fixed in 4.18.0-477.10.1.el8_8
- kernel-tools-libs-devel Fixed in 4.18.0-477.10.1.el8_8
- kernel-zfcpdump Fixed in 4.18.0-477.10.1.el8_8
- kernel-zfcpdump-core Fixed in 4.18.0-477.10.1.el8_8
- kernel-zfcpdump-devel Fixed in 4.18.0-477.10.1.el8_8
- kernel-zfcpdump-modules Fixed in 4.18.0-477.10.1.el8_8
- kernel-zfcpdump-modules-extra Fixed in 4.18.0-477.10.1.el8_8
- perf Fixed in 4.18.0-477.10.1.el8_8
- python3-perf Fixed in 4.18.0-477.10.1.el8_8
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
CloudLinux 8
- bpftool Fixed in 4.18.0-477.10.1.el8_8
- kernel Fixed in 4.18.0-477.10.1.el8_8
- kernel-abi-stablelists Fixed in 4.18.0-477.10.1.el8_8
- kernel-core Fixed in 4.18.0-477.10.1.el8_8
- kernel-cross-headers Fixed in 4.18.0-477.10.1.el8_8
- kernel-debug Fixed in 4.18.0-477.10.1.el8_8
- kernel-debug-core Fixed in 4.18.0-477.10.1.el8_8
- kernel-debug-devel Fixed in 4.18.0-477.10.1.el8_8
- kernel-debug-modules Fixed in 4.18.0-477.10.1.el8_8
- kernel-debug-modules-extra Fixed in 4.18.0-477.10.1.el8_8
- kernel-devel Fixed in 4.18.0-477.10.1.el8_8
- kernel-doc Fixed in 4.18.0-477.10.1.el8_8
- kernel-modules Fixed in 4.18.0-477.10.1.el8_8
- kernel-modules-extra Fixed in 4.18.0-477.10.1.el8_8
- kernel-rt Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-core Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug-core Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug-devel Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug-kvm Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug-modules Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-debug-modules-extra Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-devel Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-kvm Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-modules Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-rt-modules-extra Fixed in 4.18.0-477.10.1.rt7.274.el8_8
- kernel-tools Fixed in 4.18.0-477.10.1.el8_8
- kernel-tools-libs Fixed in 4.18.0-477.10.1.el8_8
- kernel-tools-libs-devel Fixed in 4.18.0-477.10.1.el8_8
- kernel-zfcpdump Fixed in 4.18.0-477.10.1.el8_8
- kernel-zfcpdump-core Fixed in 4.18.0-477.10.1.el8_8
- kernel-zfcpdump-devel Fixed in 4.18.0-477.10.1.el8_8
- kernel-zfcpdump-modules Fixed in 4.18.0-477.10.1.el8_8
- kernel-zfcpdump-modules-extra Fixed in 4.18.0-477.10.1.el8_8
- perf Fixed in 4.18.0-477.10.1.el8_8
- python3-perf Fixed in 4.18.0-477.10.1.el8_8
Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Debian 12
- linux Fixed in 5.14.6-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- linux Fixed in 5.14.6-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- linux Fixed in 5.14.6-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 16.04 LTS
- linux-hwe-edge No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 18.04 LTS
- linux Fixed in 4.15.0-192.203
- linux-aws Fixed in 4.15.0-1140.151
- linux-aws-5.0 No fix yet
- linux-aws-5.3 No fix yet
- linux-aws-5.4 Fixed in 5.4.0-1084.91~18.04.1
- linux-azure No fix yet
- linux-azure-4.15 Fixed in 4.15.0-1150.165
- linux-azure-5.3 No fix yet
- linux-azure-5.4 Fixed in 5.4.0-1090.95~18.04.1
- linux-azure-edge No fix yet
- linux-dell300x Fixed in 4.15.0-1052.57
- linux-gcp No fix yet
- linux-gcp-4.15 Fixed in 4.15.0-1135.151
- linux-gcp-5.3 No fix yet
- linux-gcp-5.4 Fixed in 5.4.0-1087.95~18.04.1
- linux-gke-4.15 No fix yet
- linux-gke-5.4 No fix yet
- linux-gkeop-5.4 No fix yet
- linux-hwe No fix yet
- linux-hwe-5.4 Fixed in 5.4.0-125.141~18.04.1
- linux-hwe-edge No fix yet
- linux-ibm-5.4 Fixed in 5.4.0-1032.36~18.04.1
- linux-kvm Fixed in 4.15.0-1126.131
- linux-oem No fix yet
- linux-oracle Fixed in 4.15.0-1105.116
- linux-oracle-5.0 No fix yet
- linux-oracle-5.3 No fix yet
- linux-oracle-5.4 Fixed in 5.4.0-1082.90~18.04.1
- linux-raspi-5.4 Fixed in 5.4.0-1069.79~18.04.1
- linux-raspi2 Fixed in 4.15.0-1118.126
- linux-snapdragon Fixed in 4.15.0-1136.146
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 20.04 LTS
- linux Fixed in 5.4.0-125.141
- linux-aws Fixed in 5.4.0-1084.91
- linux-aws-5.11 No fix yet
- linux-aws-5.13 No fix yet
- linux-aws-5.8 No fix yet
- linux-azure Fixed in 5.4.0-1090.95
- linux-azure-5.11 No fix yet
- linux-azure-5.13 No fix yet
- linux-azure-5.8 No fix yet
- linux-bluefield Fixed in 5.4.0-1045.50
- linux-gcp Fixed in 5.4.0-1087.95
- linux-gcp-5.11 No fix yet
- linux-gcp-5.13 No fix yet
- linux-gcp-5.8 No fix yet
- linux-gke Fixed in 5.4.0-1081.87
- linux-gkeop Fixed in 5.4.0-1052.55
- linux-hwe-5.11 No fix yet
- linux-hwe-5.13 No fix yet
- linux-hwe-5.8 No fix yet
- linux-ibm Fixed in 5.4.0-1032.36
- linux-intel-5.13 No fix yet
- linux-iot Fixed in 5.4.0-1004.6
- linux-kvm Fixed in 5.4.0-1074.79
- linux-oem-5.10 No fix yet
- linux-oem-5.13 No fix yet
- linux-oem-5.6 No fix yet
- linux-oracle Fixed in 5.4.0-1082.90
- linux-oracle-5.11 No fix yet
- linux-oracle-5.13 No fix yet
- linux-oracle-5.8 No fix yet
- linux-raspi Fixed in 5.4.0-1069.79
- linux-raspi2 No fix yet
- linux-riscv No fix yet
- linux-riscv-5.11 No fix yet
- linux-riscv-5.8 No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 22.04 LTS
- linux-intel-iot-realtime No fix yet
- linux-realtime No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 24.04 LTS
- linux-raspi-realtime No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 14.04 LTS
- linux No fix yet
- linux-aws Fixed in 4.4.0-1113.119Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-azure Fixed in 4.15.0-1150.165~14.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-lts-xenial Fixed in 4.4.0-234.268~14.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro 16.04 LTS
- linux Fixed in 4.4.0-234.268Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-aws Fixed in 4.4.0-1150.165Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-aws-hwe Fixed in 4.15.0-1140.151~16.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-azure Fixed in 4.15.0-1150.165~16.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-gcp Fixed in 4.15.0-1135.151~16.04.2Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-hwe Fixed in 4.15.0-192.203~16.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-kvm Fixed in 4.4.0-1114.124Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
- linux-oracle Fixed in 4.15.0-1105.116~16.04.1Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS-updates 16.04 LTS
- linux-fips Fixed in 4.4.0-1083.90Available with Ubuntu Pro: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS-updates 18.04 LTS
- linux-aws-fips Fixed in 4.15.0-2079.84Available with Ubuntu Pro: https://ubuntu.com/pro
- linux-azure-fips Fixed in 4.15.0-2060.66Available with Ubuntu Pro: https://ubuntu.com/pro
- linux-fips Fixed in 4.15.0-1097.108Available with Ubuntu Pro: https://ubuntu.com/pro
- linux-gcp-fips Fixed in 4.15.0-2044.49Available with Ubuntu Pro: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS-updates 20.04 LTS
- linux-aws-fips Fixed in 5.4.0-1085.92+fips1Available with Ubuntu Pro: https://ubuntu.com/pro
- linux-azure-fips Fixed in 5.4.0-1090.95+fips1Available with Ubuntu Pro: https://ubuntu.com/pro
- linux-fips Fixed in 5.4.0-1060.68Available with Ubuntu Pro: https://ubuntu.com/pro
- linux-gcp-fips Fixed in 5.4.0-1087.95+fips1Available with Ubuntu Pro: https://ubuntu.com/pro
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS 16.04 LTS
- linux-fips No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS 18.04 LTS
- linux-aws-fips No fix yet
- linux-azure-fips No fix yet
- linux-fips No fix yet
- linux-gcp-fips No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu Pro FIPS 20.04 LTS
- linux-aws-fips No fix yet
- linux-azure-fips No fix yet
- linux-fips No fix yet
- linux-gcp-fips No fix yet
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.