GRUB2: avoid loading unsigned kernels when GRUB is booted directly under secureboot without shim
13Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.4epss 1.4%
exploitation probability
1.4%top 30% of all CVEs
observed exploitation
nono source reports it
GRUB2 fails to validate kernel signature when booted directly without shim, allowing secure boot to be bypassed. This only affects systems where the kernel signing certificate has been imported directly into the secure boot database and the GRUB image is booted directly without the use of shim. This issue affects GRUB2 version 2.04 and prior versions.
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
Affected products
Ubuntu · grub2 in UbuntuReferences
http://lists.opensuse.org/opensuse-security-announce/2020-08/msg00067.htmlhttp://lists.opensuse.org/opensuse-security-announce/2020-08/msg00069.htmlhttps://access.redhat.com/security/vulnerabilities/grub2bootloaderhttps://lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.htmlhttps://portal.msrc.microsoft.com/en-US/security-guidance/advisory/ADV200011https://security.gentoo.org/glsa/202104-05https://security.netapp.com/advisory/ntap-20200731-0008/https://usn.ubuntu.com/4432-1/https://wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypasshttps://www.debian.org/security/2020-GRUB-UEFI-SecureBoothttps://www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/https://www.openwall.com/lists/oss-security/2020/07/29/3