Vulnerability · Published Jul 18, 2022 · Assigned by openEuler
CVE-2021-33656
Medium 6.8
In plain English
A medium-severity out-of-bounds write in openEuler:kernel. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 49% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)6.8Medium
Exploit odds (30 days)0.6%top 50.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
When setting font with malicous data by ioctl cmd PIO_FONT,kernel will write memory out of bounds.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | bpftool | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-abi-stablelists | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-core | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-cross-headers | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-debug | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-debug-core | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-debug-devel | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-debug-modules | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-debug-modules-extra | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-devel | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-doc | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-modules | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-modules-extra | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-rt | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-rt-core | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-rt-debug | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-rt-debug-core | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-rt-debug-devel | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-rt-debug-kvm | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-rt-debug-modules | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-rt-debug-modules-extra | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-rt-devel | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-rt-kvm | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-rt-modules | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-rt-modules-extra | 4.18.0-477.10.1.rt7.274.el8_8 | ALSA-2023:2736 |
| AlmaLinux:8 | kernel-tools | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-tools-libs | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-tools-libs-devel | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-zfcpdump | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-zfcpdump-core | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-zfcpdump-devel | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-zfcpdump-modules | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | kernel-zfcpdump-modules-extra | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | perf | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| AlmaLinux:8 | python3-perf | 4.18.0-477.10.1.el8_8 | ALSA-2023:2951 |
| Debian:12 | linux | 5.14.6-1 | DEBIAN-CVE-2021-33656 |
| Debian:13 | linux | 5.14.6-1 | DEBIAN-CVE-2021-33656 |
| Debian:14 | linux | 5.14.6-1 | DEBIAN-CVE-2021-33656 |
| Ubuntu:22.04:LTS | linux-intel-iot-realtime | no fix listed | UBUNTU-CVE-2021-33656 |
| Ubuntu:24.04:LTS | linux-raspi-realtime | no fix listed | UBUNTU-CVE-2021-33656 |
| Ubuntu:22.04:LTS | linux-realtime | no fix listed | UBUNTU-CVE-2021-33656 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| n/a | openEuler:kernel | <5.10.127 |
Weakness: CWE-787
References
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patch x_refsource_MISC
- https://www.openeuler.org/en/security/cve/detail.html?id=CVE-2021-33656&packageName=kernel x_refsource_MISC
- [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) mailing-list, x_refsource_MLIST
- [debian-lts-announce] 20221002 [SECURITY] [DLA 3131-1] linux security update mailing-list, x_refsource_MLIST