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Vulnerability · Published Jul 29, 2020 · Assigned by canonical

CVE-2020-15705GRUB2: avoid loading unsigned kernels when GRUB is booted directly under secureboot without shim

Medium 6.4

In plain English

A medium-severity security flaw in grub2 in Ubuntu from Ubuntu. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.4% (higher than 72% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.4Medium
Exploit odds (30 days)1.4%top 27.5% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20grub2.06-r0ALPINE-CVE-2020-15705
Alpine:v3.21grub2.06-r0ALPINE-CVE-2020-15705
Alpine:v3.22grub2.06-r0ALPINE-CVE-2020-15705
Alpine:v3.23grub2.06-r0ALPINE-CVE-2020-15705
Alpine:v3.24grub2.06-r0ALPINE-CVE-2020-15705

Affected products (as reported)

VendorProductVersions
Ubuntu grub2 in Ubuntu 20.04 LTS – before 2.04-1ubuntu26.118.04 LTS – before 2.02-2ubuntu8.1616.04 LTS – before 2.02~beta2-36ubuntu3.2614.04 ESM – before 2.02~beta2-9ubuntu1.20

Weakness: CWE-347 · Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

References