CVE-2021-43784
6.0 · MEDIUMOverview
CVE-2021-43784 is a medium-severity vulnerability affecting linuxfoundation runc. It was published on December 6, 2021 and has a CVSS 3.1 base score of 6.0 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 6.0, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
runc is a CLI tool for spawning and running containers on Linux according to the OCI specification. In runc, netlink is used internally as a serialization system for specifying the relevant container configuration to the `C` portion of the code (responsible for the based namespace setup of containers). In all versions of runc prior to 1.0.3, the encoder did not handle the possibility of an integer overflow in the 16-bit length field for the byte array attribute type, meaning that a large enough malicious byte array attribute could result in the length overflowing and the attribute contents being parsed as netlink messages for container configuration. This vulnerability requires the attacker to have some control over the configuration of the container and would allow the attacker to bypass the namespace restrictions of the container by simply adding their own netlink payload which disables all namespaces. The main users impacted are those who allow untrusted images with untrusted config
Remediation
Check the references section for vendor advisories and patches from linuxfoundation. Update runc to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linuxfoundation | runc | >= 0, < 1.0.3 | Affected |
References
Frequently Asked Questions
What is CVE-2021-43784?
CVE-2021-43784 is a medium-severity vulnerability affecting linuxfoundation runc. It was published on December 6, 2021 and has a CVSS 3.1 base score of 6.0 (MEDIUM).
How severe is CVE-2021-43784?
This vulnerability has a CVSS 3.1 base score of 6.0, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2021-43784?
Check the references section for vendor advisories and patches from linuxfoundation. Update runc to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-43784?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-43784 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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