# CVE-2020-15705: GRUB2: avoid loading unsigned kernels when GRUB is booted directly under secureboot without shim > Attackers can bypass Secure Boot to load unsigned kernels when GRUB is booted directly without shim in specific configurations. - **Severity:** Medium 6.4 (`CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Login needed:** An administrator - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 29 Jul 2020 - **Updated:** 17 Sep 2024 - **Also known as:** ALPINE-CVE-2020-15705, GHSA-w739-fjv8-98pq, SUSE-SU-2020:14461-1, SUSE-SU-2020:2303-1, SUSE-SU-2020:2304-1, SUSE-SU-2020:2305-1, SUSE-SU-2020:2306-1, SUSE-SU-2020:2307-1, SUSE-SU-2020:2308-1, UBUNTU-CVE-2020-15705, openSUSE-SU-2020:1280-1, openSUSE-SU-2020:1282-1 ## What is CVE-2020-15705? CVE-2020-15705 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 29 Jul 2020. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description 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. Weakness: CWE-347 (Improper Verification of Cryptographic Signature) ## Which versions are affected by CVE-2020-15705? It affects 14 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `grub2` | SUSE:Enterprise Storage 5 | All versions | 2.02-4.61.1 | | `grub2` | SUSE:HPE Helion OpenStack 8 | All versions | 2.02-4.61.1 | | `grub2` | SUSE:Linux Enterprise High Performance Computing 15-ESPOS | All versions | 2.02-19.56.1 | | `grub2` | SUSE:Linux Enterprise High Performance Computing 15-LTSS | All versions | 2.02-19.56.1 | | `grub2` | SUSE:Linux Enterprise Module for Basesystem 15 SP1 | All versions | 2.02-26.33.1 | | `grub2` | SUSE:Linux Enterprise Module for Basesystem 15 SP2 | All versions | 2.04-9.15.1 | | `grub2` | SUSE:Linux Enterprise Module for Server Applications 15 SP1 | All versions | 2.02-26.33.1 | | `grub2` | SUSE:Linux Enterprise Module for Server Applications 15 SP2 | All versions | 2.04-9.15.1 | | `grub2` | SUSE:Linux Enterprise Server 11 SP4-LTSS | All versions | 2.00-0.66.21.1 | | `grub2` | SUSE:Linux Enterprise Server 12 SP2-BCL | All versions | 2.02~beta2-115.56.1 | | `grub2` | SUSE:Linux Enterprise Server 12 SP2-LTSS | All versions | 2.02~beta2-115.56.1 | | `grub2` | SUSE:Linux Enterprise Server 12 SP3-BCL | All versions | 2.02-4.61.1 | | `grub2` | SUSE:Linux Enterprise Server 12 SP3-LTSS | All versions | 2.02-4.61.1 | | `grub2` | SUSE:Linux Enterprise Server 12 SP4-LTSS | All versions | 2.02-12.39.1 | | `grub2` | SUSE:Linux Enterprise Server 12 SP5 | All versions | 2.02-12.39.1 | | `grub2` | SUSE:Linux Enterprise Server 15-LTSS | All versions | 2.02-19.56.1 | | `grub2` | SUSE:Linux Enterprise Server for SAP Applications 12 SP2 | All versions | 2.02~beta2-115.56.1 | | `grub2` | SUSE:Linux Enterprise Server for SAP Applications 12 SP3 | All versions | 2.02-4.61.1 | | `grub2` | SUSE:Linux Enterprise Server for SAP Applications 12 SP4 | All versions | 2.02-12.39.1 | | `grub2` | SUSE:Linux Enterprise Server for SAP Applications 12 SP5 | All versions | 2.02-12.39.1 | | `grub2` | SUSE:Linux Enterprise Server for SAP Applications 15 | All versions | 2.02-19.56.1 | | `grub2` | SUSE:OpenStack Cloud 7 | All versions | 2.02~beta2-115.56.1 | | `grub2` | SUSE:OpenStack Cloud 8 | All versions | 2.02-4.61.1 | | `grub2` | SUSE:OpenStack Cloud 9 | All versions | 2.02-12.39.1 | | `grub2` | SUSE:OpenStack Cloud Crowbar 8 | All versions | 2.02-4.61.1 | | `grub2` | SUSE:OpenStack Cloud Crowbar 9 | All versions | 2.02-12.39.1 | | `grub2` | openSUSE:Leap 15.1 | All versions | 2.02-lp151.21.27.1 | | `grub2` | openSUSE:Leap 15.2 | All versions | 2.04-lp152.7.9.1 | Products: Canonical Ubuntu Linux, Debian Debian Linux, Gnu Grub2, Microsoft Windows 10, Microsoft Windows 8.1, Microsoft Windows Rt 8.1, Microsoft Windows Server 2012, Microsoft Windows Server 2016, Microsoft Windows Server 2019, Opensuse Leap, Redhat Enterprise Linux, Redhat Enterprise Linux Atomic Host, Redhat Openshift Container Platform, Suse Suse Linux Enterprise Server. ## How do I fix CVE-2020-15705? Apply the vendor's patch. ## Is CVE-2020-15705 being exploited? There is no known exploitation of CVE-2020-15705 in the wild and no public exploit code. ## Other vulnerabilities in Canonical Ubuntu Linux - [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild) - [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild) - [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2020-15705 and fix it if it is affected. What it is: CVE-2020-15705 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 29 Jul 2020. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2020-15705 in the wild and no public exploit code. Affected product: Canonical Ubuntu Linux. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2020-15705/ (Markdown: https://insights.sbomify.com/CVE-2020-15705/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2020-15705 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-15705 - OSV: https://osv.dev/vulnerability/CVE-2020-15705 --- From sbomify Insights: https://insights.sbomify.com/CVE-2020-15705/ Summaries are generated and may contain mistakes; the official description above is the record.