# CVE-2021-3981: Information disclosure in grub2 > Local attackers can read GRUB configuration files to obtain encrypted passwords due to incorrect file permissions. - **Severity:** Low 3.3 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 8 Mar 2022 - **Updated:** 13 Feb 2025 - **Also known as:** ALSA-2022:2110, AZL-34786, AZL-8937, DEBIAN-CVE-2021-3981, GHSA-6hfm-rxpf-979r, OESA-2022-1597, RHSA-2022:2110, RLSA-2022:2110, UBUNTU-CVE-2021-3981, openSUSE-SU-2024:11700-1 ## What is CVE-2021-3981? CVE-2021-3981 is a low-severity vulnerability in Fedoraproject Fedora, published on 8 Mar 2022. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description A flaw in grub2 was found where its configuration file, known as grub.cfg, is being created with the wrong permission set allowing non privileged users to read its content. This represents a low severity confidentiality issue, as those users can eventually read any encrypted passwords present in grub.cfg. This flaw affects grub2 2.06 and previous versions. This issue has been fixed in grub upstream but no version with the fix is currently released. Weakness: CWE-276 (Incorrect Default Permissions) ## Which versions are affected by CVE-2021-3981? It affects 2 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `grub2-common` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-efi-aa64` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-efi-aa64-cdboot` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-efi-aa64-modules` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-efi-ia32` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-efi-ia32-cdboot` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-efi-ia32-modules` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-efi-x64` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-efi-x64-cdboot` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-efi-x64-modules` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-pc` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-pc-modules` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-ppc64le` | AlmaLinux:8 | All versions | 1:2.02-123.el8_6.8.alma | | `grub2-ppc64le-modules` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-tools` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-tools-efi` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-tools-extra` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2-tools-minimal` | AlmaLinux:8 | All versions | 1:2.02-123.el8.alma | | `grub2` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-common` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-debugsource` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-efi-aa64` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-efi-aa64-cdboot` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-efi-aa64-modules` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-efi-ia32` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-efi-ia32-cdboot` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-efi-ia32-modules` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-efi-x64` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-efi-x64-cdboot` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-efi-x64-modules` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-pc` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-pc-modules` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-ppc64le` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-ppc64le-modules` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-tools` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-tools-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-tools-efi` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-tools-efi-debuginfo` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | | `grub2-tools-extra` | Red Hat:enterprise_linux:8::baseos | All versions | 1:2.02-123.el8 | Products: Fedoraproject Fedora, Gnu Grub2. ## How do I fix CVE-2021-3981? No fix published yet. ## Is CVE-2021-3981 being exploited? There is no known exploitation of CVE-2021-3981 in the wild and no public exploit code. ## Other vulnerabilities in Fedoraproject Fedora - [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild) - [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild) - [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2021-3981 and fix it if it is affected. What it is: CVE-2021-3981 is a low-severity vulnerability in Fedoraproject Fedora, published on 8 Mar 2022. 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-2021-3981 in the wild and no public exploit code. Affected product: Fedoraproject Fedora. 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-2021-3981/ (Markdown: https://insights.sbomify.com/CVE-2021-3981/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3981 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3981 - OSV: https://osv.dev/vulnerability/CVE-2021-3981 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-3981/ Summaries are generated and may contain mistakes; the official description above is the record.