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Vulnerability · Published Jul 29, 2020 · Assigned by canonical

CVE-2020-15706GRUB2 contains a race condition leading to a use-after-free vulnerability which can be triggered by redefining a function whilst the same function is already executing.

Medium 6.4

In plain English

A medium-severity race condition 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 1.0% (higher than 62% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.4Medium
Exploit odds (30 days)1.0%top 37.7% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known

Official description

GRUB2 contains a race condition in grub_script_function_create() leading to a use-after-free vulnerability which can be triggered by redefining a function whilst the same function is already executing, leading to arbitrary code execution and secure boot restriction bypass. This issue affects GRUB2 version 2.04 and prior versions.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.20grub2.06-r0ALPINE-CVE-2020-15706
Alpine:v3.21grub2.06-r0ALPINE-CVE-2020-15706
Alpine:v3.22grub2.06-r0ALPINE-CVE-2020-15706
Alpine:v3.23grub2.06-r0ALPINE-CVE-2020-15706
Alpine:v3.24grub2.06-r0ALPINE-CVE-2020-15706
Debian:12grub22.04-9DEBIAN-CVE-2020-15706
Debian:13grub22.04-9DEBIAN-CVE-2020-15706
Debian:14grub22.04-9DEBIAN-CVE-2020-15706

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-362 · Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

References