# CVE-2021-20188: Improper Authorization in github.com/containers/libpod > Low-privileged users in privileged Podman containers can bypass file permission checks to access or modify root-owned files, compromising data confidentiality and integrity. - **Severity:** High 7.0 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H`) - **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:** 11 Feb 2021 - **Updated:** 3 Aug 2024 - **Also known as:** ALSA-2021:0705, DEBIAN-CVE-2021-20188, GHSA-9h63-7qf6-mv6r, GO-2022-0641, OESA-2021-1123, RHSA-2021:0681, RHSA-2021:0705, RHSA-2021:0710, RLSA-2021:0705, RLSA-2021:0706, UBUNTU-CVE-2021-20188 ## What is CVE-2021-20188? CVE-2021-20188 is a high-severity missing authorization vulnerability in Redhat Enterprise Linux, published on 11 Feb 2021. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description A flaw was found in podman before 1.7.0. File permissions for non-root users running in a privileged container are not correctly checked. This flaw can be abused by a low-privileged user inside the container to access any other file in the container, even if owned by the root user inside the container. It does not allow to directly escape the container, though being a privileged container means that a lot of security features are disabled when running the container. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability. Weakness: CWE-863 (Incorrect Authorization) ## Which versions are affected by CVE-2021-20188? 3 open source packages ship an affected version, including github.com/containers/libpod. It affects 3 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/containers/libpod` | Go | All versions | 1.7.0 | | `github.com/containers/libpod` | Go | All versions | 1.7.0 | | `github.com/containers/libpod` | Go | All versions | 1.7.0 | | `buildah` | AlmaLinux:8 | All versions | 1.5-8.gite94b4f9.module_el8.3.0+2044+12421f43 | | `buildah` | AlmaLinux:8 | All versions | 1.5-8.gite94b4f9.module_el8.4.0+2496+12421f43 | | `buildah` | AlmaLinux:8 | All versions | 1.5-8.gite94b4f9.module_el8.5.0+119+9a9ec082 | | `container-selinux` | AlmaLinux:8 | All versions | 2:2.124.0-1.gitf958d0c.module_el8.3.0+2044+12421f43 | | `containernetworking-plugins` | AlmaLinux:8 | All versions | 0.7.4-4.git9ebe139.module_el8.3.0+2044+12421f43 | | `containernetworking-plugins` | AlmaLinux:8 | All versions | 0.7.4-4.git9ebe139.module_el8.4.0+2496+12421f43 | | `containernetworking-plugins` | AlmaLinux:8 | All versions | 0.7.4-4.git9ebe139.module_el8.5.0+119+9a9ec082 | | `containers-common` | AlmaLinux:8 | All versions | 1:0.1.32-6.git1715c90.module_el8.4.0+2478+12421f43 | | `containers-common` | AlmaLinux:8 | All versions | 1:0.1.32-6.git1715c90.module_el8.4.0+2496+12421f43 | | `containers-common` | AlmaLinux:8 | All versions | 1:0.1.32-6.git1715c90.module_el8.5.0+119+9a9ec082 | | `crit` | AlmaLinux:8 | All versions | 3.12-9.module_el8.3.0+2044+12421f43 | | `crit` | AlmaLinux:8 | All versions | 3.12-9.module_el8.4.0+2496+12421f43 | | `crit` | AlmaLinux:8 | All versions | 3.12-9.module_el8.5.0+119+9a9ec082 | | `criu` | AlmaLinux:8 | All versions | 3.12-9.module_el8.3.0+2044+12421f43 | | `criu` | AlmaLinux:8 | All versions | 3.12-9.module_el8.4.0+2496+12421f43 | | `criu` | AlmaLinux:8 | All versions | 3.12-9.module_el8.5.0+119+9a9ec082 | | `fuse-overlayfs` | AlmaLinux:8 | All versions | 0.3-5.module_el8.3.0+2044+12421f43 | | `fuse-overlayfs` | AlmaLinux:8 | All versions | 0.3-5.module_el8.4.0+2496+12421f43 | | `fuse-overlayfs` | AlmaLinux:8 | All versions | 0.3-5.module_el8.5.0+119+9a9ec082 | | `oci-systemd-hook` | AlmaLinux:8 | All versions | 1:0.1.15-2.git2d0b8a3.module_el8.3.0+2044+12421f43 | | `oci-systemd-hook` | AlmaLinux:8 | All versions | 1:0.1.15-2.git2d0b8a3.module_el8.4.0+2496+12421f43 | | `oci-systemd-hook` | AlmaLinux:8 | All versions | 1:0.1.15-2.git2d0b8a3.module_el8.5.0+119+9a9ec082 | | `oci-umount` | AlmaLinux:8 | All versions | 2:2.3.4-2.git87f9237.module_el8.3.0+2044+12421f43 | | `oci-umount` | AlmaLinux:8 | All versions | 2:2.3.4-2.git87f9237.module_el8.4.0+2496+12421f43 | | `oci-umount` | AlmaLinux:8 | All versions | 2:2.3.4-2.git87f9237.module_el8.5.0+119+9a9ec082 | | `podman` | AlmaLinux:8 | All versions | 1.0.0-8.git921f98f.module_el8.3.0+2044+12421f43 | | `podman` | AlmaLinux:8 | All versions | 1.0.0-8.git921f98f.module_el8.4.0+2496+12421f43 | | `podman` | AlmaLinux:8 | All versions | 1.0.0-8.git921f98f.module_el8.5.0+119+9a9ec082 | | `podman-docker` | AlmaLinux:8 | All versions | 1.0.0-8.git921f98f.module_el8.3.0+2044+12421f43 | | `python3-criu` | AlmaLinux:8 | All versions | 3.12-9.module_el8.3.0+2044+12421f43 | | `python3-criu` | AlmaLinux:8 | All versions | 3.12-9.module_el8.4.0+2496+12421f43 | | `python3-criu` | AlmaLinux:8 | All versions | 3.12-9.module_el8.5.0+119+9a9ec082 | | `runc` | AlmaLinux:8 | All versions | 1.0.0-56.rc5.dev.git2abd837.module_el8.3.0+2044+12421f43 | | `runc` | AlmaLinux:8 | All versions | 1.0.0-56.rc5.dev.git2abd837.module_el8.4.0+2496+12421f43 | | `runc` | AlmaLinux:8 | All versions | 1.0.0-56.rc5.dev.git2abd837.module_el8.5.0+119+9a9ec082 | | `skopeo` | AlmaLinux:8 | All versions | 1:0.1.32-6.git1715c90.module_el8.4.0+2478+12421f43 | | `skopeo` | AlmaLinux:8 | All versions | 1:0.1.32-6.git1715c90.module_el8.4.0+2496+12421f43 | Products: Podman Project Podman, Redhat Enterprise Linux, Redhat Openshift Container Platform. ## How do I fix CVE-2021-20188? Upgrade github.com/containers/libpod to 1.7.0 or later. ## Is CVE-2021-20188 being exploited? There is no known exploitation of CVE-2021-20188 in the wild and no public exploit code. ## Other vulnerabilities in Redhat Enterprise Linux - [CVE-2026-57231](https://insights.sbomify.com/CVE-2026-57231/): Podman: Malformed Image can trick podman run into leaking host environment variables into the container (high 7.5) - [CVE-2022-2738](https://insights.sbomify.com/CVE-2022-2738/): Use after free in podman (high 7.5) - [CVE-2022-2989](https://insights.sbomify.com/CVE-2022-2989/): Podman's incorrect handling of the supplementary groups may lead to data disclosure, modification (high 7.1) - [CVE-2023-0778](https://insights.sbomify.com/CVE-2023-0778/): Podman Time-of-check Time-of-use (TOCTOU) Race Condition (medium 6.8) - [CVE-2019-25067](https://insights.sbomify.com/CVE-2019-25067/): Podman/Varlink API Privilege Escalation (medium 6.3) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2021-20188 and fix it if it is affected. What it is: CVE-2021-20188 is a high-severity missing authorization vulnerability in Redhat Enterprise Linux, published on 11 Feb 2021. 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-2021-20188 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/containers/libpod (Go): affected all versions; fixed in 1.7.0 - github.com/containers/libpod (Go): affected all versions; fixed in 1.7.0 - github.com/containers/libpod (Go): affected all versions; fixed in 1.7.0 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-2021-20188/ (Markdown: https://insights.sbomify.com/CVE-2021-20188/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20188 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20188 - OSV: https://osv.dev/vulnerability/CVE-2021-20188 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-20188/ Summaries are generated and may contain mistakes; the official description above is the record.