Vulnerability in GNU Grub2
CVE-2020-15705
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.
Published · last modified .
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.
EPSS exploit prediction
EPSS: 0.014 (71.3th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 71st percentile — 71.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000
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 Linux — versions 10.0
- openSUSE Leap — versions 15.1, 15.2
Weakness classification (CWE)
Public proof-of-concept exploits
References
- www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/ (Third Party Advisory)
- wiki.ubuntu.com/SecurityTeam/KnowledgeBase/GRUB2SecureBootBypass (vendor-advisory, Third Party Advisory)
- ubuntu.com/security/notices/USN-4432-1 (vendor-advisory, Third Party Advisory)
- www.debian.org/security/2020-GRUB-UEFI-SecureBoot (vendor-advisory, Third Party Advisory)
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/ADV200011 (Patch, Third Party Advisory, Vendor Advisory)
- access.redhat.com/security/vulnerabilities/grub2bootloader (vendor-advisory, Third Party Advisory)
- www.suse.com/c/suse-addresses-grub2-secure-boot-issue/ (vendor-advisory, Third Party Advisory)
- www.suse.com/support/kb/doc/ (vendor-advisory, Third Party Advisory)
- www.openwall.com/lists/oss-security/2020/07/29/3 (Mailing List, Third Party Advisory)
- lists.gnu.org/archive/html/grub-devel/2020-07/msg00034.html (Issue Tracking, Vendor Advisory)
Frequently asked questions
- What is CVE-2020-15705?
- CVE-2020-15705 is a medium-severity vulnerability in GNU Grub2, classified under Improper Verification of Cryptographic Signature. CVSS score: 6.4/10. Published 2020-07-29.
- How severe is CVE-2020-15705?
- Medium severity. CVSS v3 base score is 6.4 out of 10.
- Is CVE-2020-15705 known to be exploited?
- 27 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.