CVE Vulnerabilities

CVE-2020-25632

Use After Free

Published: Mar 03, 2021 | Modified: Nov 21, 2024
CVSS 3.x
8.2
HIGH
Source:
NVD
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
CVSS 2.x
7.2 HIGH
AV:L/AC:L/Au:N/C:C/I:C/A:C
RedHat/V2
RedHat/V3
7.5 MODERATE
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
Ubuntu
MEDIUM

A flaw was found in grub2 in versions prior to 2.06. The rmmod implementation allows the unloading of a module used as a dependency without checking if any other dependent module is still loaded leading to a use-after-free scenario. This could allow arbitrary code to be executed or a bypass of Secure Boot protections. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Name Vendor Start Version End Version
Grub2 Gnu * 2.06 (excluding)
Red Hat Enterprise Linux 7 RedHat grub2-1:2.02-0.87.el7_9.2 *
Red Hat Enterprise Linux 7.2 Advanced Update Support RedHat grub2-1:2.02-0.86.el7_2.2 *
Red Hat Enterprise Linux 7.3 Advanced Update Support RedHat grub2-1:2.02-0.86.el7_3.2 *
Red Hat Enterprise Linux 7.4 Advanced Update Support RedHat grub2-1:2.02-0.86.el7_4.2 *
Red Hat Enterprise Linux 7.4 Telco Extended Update Support RedHat grub2-1:2.02-0.86.el7_4.2 *
Red Hat Enterprise Linux 7.4 Update Services for SAP Solutions RedHat grub2-1:2.02-0.86.el7_4.2 *
Red Hat Enterprise Linux 7.6 Extended Update Support RedHat grub2-1:2.02-0.86.el7_6.3 *
Red Hat Enterprise Linux 7.7 Extended Update Support RedHat grub2-1:2.02-0.86.el7_7.3 *
Red Hat Enterprise Linux 8 RedHat grub2-1:2.02-90.el8_3.1 *
Red Hat Enterprise Linux 8 RedHat shim-0:15.4-2.el8_1 *
Red Hat Enterprise Linux 8 RedHat shim-unsigned-aarch64-0:15-7.el8_1 *
Red Hat Enterprise Linux 8 RedHat shim-unsigned-x64-0:15.4-4.el8_1 *
Red Hat Enterprise Linux 8 RedHat fwupd-0:1.5.9-1.el8_4 *
Red Hat Enterprise Linux 8.1 Extended Update Support RedHat grub2-1:2.02-87.el8_1.2 *
Red Hat Enterprise Linux 8.1 Extended Update Support RedHat fwupd-0:1.1.4-4.el8_1 *
Red Hat Enterprise Linux 8.1 Extended Update Support RedHat shim-0:15.4-2.el8_1 *
Red Hat Enterprise Linux 8.1 Extended Update Support RedHat shim-unsigned-aarch64-0:15-7.el8_1 *
Red Hat Enterprise Linux 8.1 Extended Update Support RedHat shim-unsigned-x64-0:15.4-4.el8_1 *
Red Hat Enterprise Linux 8.2 Extended Update Support RedHat grub2-1:2.02-87.el8_2.3 *
Red Hat Enterprise Linux 8.2 Extended Update Support RedHat fwupd-0:1.1.4-9.el8_2 *
Red Hat Enterprise Linux 8.2 Extended Update Support RedHat shim-0:15.4-2.el8_1 *
Red Hat Enterprise Linux 8.2 Extended Update Support RedHat shim-unsigned-aarch64-0:15-7.el8_1 *
Red Hat Enterprise Linux 8.2 Extended Update Support RedHat shim-unsigned-x64-0:15.4-4.el8_1 *
Grub2 Ubuntu bionic *
Grub2 Ubuntu trusty *
Grub2 Ubuntu xenial *
Grub2-signed Ubuntu bionic *
Grub2-signed Ubuntu esm-infra-legacy/trusty *
Grub2-signed Ubuntu esm-infra/bionic *
Grub2-signed Ubuntu esm-infra/focal *
Grub2-signed Ubuntu esm-infra/xenial *
Grub2-signed Ubuntu focal *
Grub2-signed Ubuntu groovy *
Grub2-signed Ubuntu hirsute *
Grub2-signed Ubuntu impish *
Grub2-signed Ubuntu trusty *
Grub2-signed Ubuntu trusty/esm *
Grub2-signed Ubuntu xenial *
Grub2-unsigned Ubuntu bionic *
Grub2-unsigned Ubuntu esm-infra/bionic *
Grub2-unsigned Ubuntu esm-infra/focal *
Grub2-unsigned Ubuntu esm-infra/xenial *
Grub2-unsigned Ubuntu focal *
Grub2-unsigned Ubuntu groovy *
Grub2-unsigned Ubuntu hirsute *
Grub2-unsigned Ubuntu impish *
Grub2-unsigned Ubuntu precise/esm *
Grub2-unsigned Ubuntu trusty *
Grub2-unsigned Ubuntu xenial *

Potential Mitigations

References