# CVE-2021-41103: Insufficiently restricted permissions on plugin directories > Unprivileged host users can access and modify container files due to insufficient directory permissions in containerd. - **Severity:** Medium 5.9 (`CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 4 Oct 2021 - **Updated:** 4 Aug 2024 - **Also known as:** AZL-6681, CLEANSTART-2025-SC08629, DEBIAN-CVE-2021-41103, DSA-5002-1, GHSA-c2h3-6mxw-7mvq, GO-2022-0938, OESA-2021-1428, UBUNTU-CVE-2021-41103, USN-5100-1, openSUSE-SU-2024:11565-1 ## What is CVE-2021-41103? CVE-2021-41103 is a medium-severity missing authorization vulnerability in Debian Debian Linux, published on 4 Oct 2021. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description containerd is an open source container runtime with an emphasis on simplicity, robustness and portability. A bug was found in containerd where container root directories and some plugins had insufficiently restricted permissions, allowing otherwise unprivileged Linux users to traverse directory contents and execute programs. When containers included executable programs with extended permission bits (such as setuid), unprivileged Linux users could discover and execute those programs. When the UID of an unprivileged Linux user on the host collided with the file owner or group inside a container, the unprivileged Linux user on the host could discover, read, and modify those files. This vulnerability has been fixed in containerd 1.4.11 and containerd 1.5.7. Users should update to these version when they are released and may restart containers or update directory permissions to mitigate the vulnerability. Users unable to update should limit access to the host to trusted users. Update directory permission on container bundles directories. Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) ## Which versions are affected by CVE-2021-41103? 5 open source packages ship an affected version, including github.com/containerd/containerd. It affects 3 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/containerd/containerd` | Go | All versions | 1.4.11, 1.5.7 | | `github.com/containerd/containerd` | Go | All versions | 1.4.11 | | `github.com/containerd/containerd` | Go | All versions | 1.4.11 | | `github.com/containerd/containerd` | Go | From 1.5.0 | 1.5.7 | | `github.com/containerd/containerd` | Go | From 1.5.0 | 1.5.7 | | `containerd` | openSUSE:Tumbleweed | All versions | 1.4.11-1.1 | Products: Debian Debian Linux, Fedoraproject Fedora, Linuxfoundation Containerd. ## How do I fix CVE-2021-41103? Upgrade github.com/containerd/containerd to a fixed version for your release line: 1.4.11 or 1.5.7. ## Is CVE-2021-41103 being exploited? There is no known exploitation of CVE-2021-41103 in the wild and no public exploit code. ## Other vulnerabilities in Debian Debian Linux - [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild) - [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild) - [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild) - [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild) - [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2021-41103 and fix it if it is affected. What it is: CVE-2021-41103 is a medium-severity missing authorization vulnerability in Debian Debian Linux, published on 4 Oct 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-2021-41103 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/containerd/containerd (Go): affected all versions; fixed in 1.4.11, 1.5.7 - github.com/containerd/containerd (Go): affected all versions; fixed in 1.4.11 - github.com/containerd/containerd (Go): affected all versions; fixed in 1.4.11 - github.com/containerd/containerd (Go): affected from 1.5.0; fixed in 1.5.7 - github.com/containerd/containerd (Go): affected from 1.5.0; fixed in 1.5.7 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-2021-41103/ (Markdown: https://insights.sbomify.com/CVE-2021-41103/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-41103 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-41103 - OSV: https://osv.dev/vulnerability/CVE-2021-41103 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-41103/ Summaries are generated and may contain mistakes; the official description above is the record.