Use After Free in Gnu Grub2
CVE-2020-15706
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.
Vulnerability class: Race Condition
EPSS: 0.010 (58.5th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Gnu Grub2
- Microsoft Windows_10 — versions 1607, 1709, 1803
- Microsoft Windows_8.1
- Microsoft Windows_rt_8.1
- Microsoft Windows_server_2012 — versions r2
- Microsoft Windows_server_2016 — versions 1903, 1909, 2004
- Microsoft Windows_server_2019
- Canonical Ubuntu_linux — versions 14.04, 16.04, 18.04
- Debian Debian_linux — versions 10.0
- Opensuse Leap — versions 15.1, 15.2
Weakness classification (CWE)
Public proof-of-concept exploits
References
- security@ubuntu.com (x_refsource_CONFIRM, Third Party Advisory)
- security@ubuntu.com (x_refsource_UBUNTU, vendor-advisory, Third Party Advisory)
- security@ubuntu.com (x_refsource_UBUNTU, vendor-advisory, Third Party Advisory)
- security@ubuntu.com (vendor-advisory, Third Party Advisory, x_refsource_DEBIAN)
- security@ubuntu.com (x_refsource_CONFIRM, Patch, Third Party Advisory, Vendor Advisory)
- security@ubuntu.com (x_refsource_REDHAT, vendor-advisory, Third Party Advisory)
- security@ubuntu.com (vendor-advisory, Third Party Advisory, x_refsource_SUSE)
- security@ubuntu.com (vendor-advisory, Third Party Advisory, x_refsource_SUSE)
- security@ubuntu.com (x_refsource_CONFIRM, Mailing List, Third Party Advisory)
- security@ubuntu.com (x_refsource_CONFIRM, Issue Tracking, Vendor Advisory)
Frequently asked questions
- What is CVE-2020-15706?
- CVE-2020-15706 is a medium-severity vulnerability in Gnu Grub2, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 6.4/10. Published 2020-07-29.
- How severe is CVE-2020-15706?
- Medium severity. CVSS v3 base score is 6.4 out of 10.
- Is CVE-2020-15706 known to be exploited?
- 13 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.