Vulnerability · Published Jul 6, 2022 · Assigned by redhat
CVE-2021-3695
Medium 4.5
In plain English
A medium-severity out-of-bounds write in grub2. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 41% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)4.5Medium
Exploit odds (30 days)0.5%top 58.8% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results, also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | grub2-common | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-common | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-efi-aa64 | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-efi-aa64 | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-efi-aa64-cdboot | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-efi-aa64-cdboot | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-efi-aa64-modules | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-efi-aa64-modules | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-efi-ia32 | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:8 | grub2-efi-ia32-cdboot | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:8 | grub2-efi-ia32-modules | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:8 | grub2-efi-x64 | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-efi-x64 | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-efi-x64-cdboot | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-efi-x64-cdboot | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-efi-x64-modules | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-efi-x64-modules | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-pc | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-pc | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-pc-modules | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-pc-modules | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:9 | grub2-ppc64le | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-ppc64le-modules | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-ppc64le-modules | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-tools | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-tools | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-tools-efi | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-tools-efi | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-tools-extra | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-tools-extra | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | grub2-tools-minimal | 1:2.02-123.el8_6.8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | grub2-tools-minimal | 1:2.06-27.el9_0.7.alma | ALSA-2022:5099 |
| AlmaLinux:8 | shim-aa64 | 15.6-1.el8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | shim-aa64 | 15.6-1.el9.alma | ALSA-2022:5099 |
| AlmaLinux:8 | shim-ia32 | 15.6-1.el8.alma | ALSA-2022:5095 |
| AlmaLinux:8 | shim-unsigned-x64 | 15.6-1.el8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | shim-unsigned-x64 | 15.6-1.el9.alma | ALSA-2022:5099 |
| AlmaLinux:8 | shim-x64 | 15.6-1.el8.alma | ALSA-2022:5095 |
| AlmaLinux:9 | shim-x64 | 15.6-1.el9.alma | ALSA-2022:5099 |
| Debian:12 | grub2 | 2.06-3 | DEBIAN-CVE-2021-3695 |
| Debian:13 | grub2 | 2.06-3 | DEBIAN-CVE-2021-3695 |
| Debian:14 | grub2 | 2.06-3 | DEBIAN-CVE-2021-3695 |
| Rocky Linux:8 | grub2 | 1:2.02-123.el8_6.8 | RLSA-2022:5095 |
| Rocky Linux:8 | mokutil | 1:0.3.0-11.el8_6.1 | RLSA-2022:5095 |
| Rocky Linux:9 | mokutil | 2:0.4.0-8.el9_0.1 | RLSA-2022:5099 |
| Rocky Linux:8 | shim | 0:15.6-1.el8 | RLSA-2022:5095 |
| Rocky Linux:9 | shim | 0:15.6-1.el9 | RLSA-2022:5099 |
| Rocky Linux:9 | shim | 0:15.6-1.el9.rocky.0.1 | RLSA-2022:5099 |
| Rocky Linux:8 | shim-unsigned-x64 | 0:15.6-1.el8 | RLSA-2022:5095 |
| Ubuntu:22.04:LTS | grub2-signed | 1.187.3~22.04.1 | USN-6355-1 |
| Ubuntu:22.04:LTS | grub2-signed | 1.187.3~22.04.1 | UBUNTU-CVE-2021-3695 |
| Ubuntu:22.04:LTS | grub2-unsigned | 2.06-2ubuntu14.1 | UBUNTU-CVE-2021-3695 |
| Ubuntu:22.04:LTS | grub2-unsigned | 2.06-2ubuntu14.1 | USN-6355-1 |
| Ubuntu:22.04:LTS | shim | 15.7-0ubuntu1 | USN-6355-1 |
| Ubuntu:22.04:LTS | shim-signed | 1.51.3 | USN-6355-1 |
Affected products (as reported)
Weakness: CWE-787
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1991685 x_refsource_MISC
- GLSA-202209-12 vendor-advisory, x_refsource_GENTOO
- https://security.netapp.com/advisory/ntap-20220930-0001/ x_refsource_CONFIRM