Summary
containerd started with non-empty inheritable Linux process capabilities
Workarounds
The entrypoint of a container can be modified to use a utility like capsh(1) to drop inheritable capabilities prior to the primary process starting.
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Impact
A bug was found in containerd where containers were incorrectly started with non-empty inheritable Linux process capabilities, creating an atypical Linux environment and enabling programs with inheritable file capabilities to elevate those capabilities to the permitted set during execve(2). Normally, when executable programs have specified permitted file capabilities, otherwise unprivileged users and processes can execute those programs and gain the specified file capabilities up to the bounding set. Due to this bug, containers which included executable programs with inheritable file capabilities allowed otherwise unprivileged users and processes to additionally gain these inheritable file capabilities up to the container's bounding set. Containers which use Linux users and groups to perform privilege separation inside the container are most directly impacted.
This bug did not affect the container security sandbox as the inheritable set never contained more capabilities than were included in the container's bounding set.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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This bug has been fixed in containerd 1.5.11 and 1.6.2. Users should update to these versions as soon as possible. Running containers should be stopped, deleted, and recreated for the inheritable capabilities to be reset.
This fix changes containerd behavior such that containers are started with a more typical Linux environment. Refer to capabilities(7) for a description of how capabilities work. Note that permitted file capabilities continue to allow for privileges to be raised up to the container's bounding set and that processes may add capabilities to their own inheritable set up to the container's bounding set per the rules described in the manual page. In all cases the container's bounding set provides an upper bound on the capabilities that can be assumed and provides for the container security sandbox.
Frequently Asked Questions
- What is GHSA-C9CP-9C75-9V8C? GHSA-C9CP-9C75-9V8C is a low-severity security vulnerability in github.com/containerd/containerd (go), affecting versions < 1.5.11. It is fixed in 1.5.11, 1.6.2.
- Which versions of github.com/containerd/containerd are affected by GHSA-C9CP-9C75-9V8C? github.com/containerd/containerd (go) versions < 1.5.11 is affected.
- Is there a fix for GHSA-C9CP-9C75-9V8C? Yes. GHSA-C9CP-9C75-9V8C is fixed in 1.5.11, 1.6.2. Upgrade to this version or later.
- Is GHSA-C9CP-9C75-9V8C exploitable, and should I be worried? Whether GHSA-C9CP-9C75-9V8C is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether GHSA-C9CP-9C75-9V8C is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix GHSA-C9CP-9C75-9V8C?
- Upgrade
github.com/containerd/containerdto 1.5.11 or later - Upgrade
github.com/containerd/containerdto 1.6.2 or later
- Upgrade