Integer overflow in GNU Grub2
CVE-2020-15707
Integer overflows were discovered in the functions grub_cmd_initrd and grub_initrd_init in the efilinux component of GRUB2, as shipped in Debian, Red Hat, and Ubuntu (the functionality is not included in GRUB2 upstream), leading to a heap-based buffer overflow. These could be triggered by an extremely large number of arguments to the initrd command on 32-bit architectures, or a crafted filesystem with very large files on any architecture. An attacker could use this to execute arbitrary code and bypass UEFI Secure Boot restrictions. This issue affects GRUB2 version 2.04 and prior versions.
Vulnerability class: Race Condition
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:H.
EPSS exploit prediction
EPSS: 0.016 (74.6th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 75th percentile — 74.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.016 · newest: 0.016 · 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
- NetApp Active Iq Unified Manager
- Canonical Ubuntu Linux — versions 14.04, 16.04, 18.04
- Debian Linux — versions 10.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- www.eclypsium.com/2020/07/29/theres-a-hole-in-the-boot/ (Exploit, 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-2020-15707?
- CVE-2020-15707 is a medium-severity vulnerability in GNU Grub2, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 5.7/10. Published 2020-07-29.
- How severe is CVE-2020-15707?
- Medium severity. CVSS v3 base score is 5.7 out of 10.
- Is CVE-2020-15707 known to be exploited?
- 12 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.