Summary
A Helm contributor discovered that a specially crafted JSON Schema within a chart can lead to a stack overflow.
Workarounds
Ensure that the JSON Schema within any charts loaded by Helm does not have a large number of nested references. These JSON Schema files are larger than 10 MiB.
For more information
Helm's security policy is spelled out in detail in our SECURITY document.
Credits
Disclosed by Jakub Ciolek at AlphaSense.
Impact
A JSON Schema file within a chart can be crafted with a deeply nested chain of references, leading to parser recursion that can exceed the stack size limit and trigger a stack overflow.
CVE-2025-32387 has a CVSS score of 6.5 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.17.3); upgrading removes the vulnerable code path.
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.
Remediation advice
This issue has been resolved in Helm v3.17.3.
Frequently Asked Questions
- What is CVE-2025-32387? CVE-2025-32387 is a medium-severity security vulnerability in helm.sh/helm/v3 (go), affecting versions < 3.17.3. It is fixed in 3.17.3.
- How severe is CVE-2025-32387? CVE-2025-32387 has a CVSS score of 6.5 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of helm.sh/helm/v3 are affected by CVE-2025-32387? helm.sh/helm/v3 (go) versions < 3.17.3 is affected.
- Is there a fix for CVE-2025-32387? Yes. CVE-2025-32387 is fixed in 3.17.3. Upgrade to this version or later.
- Is CVE-2025-32387 exploitable, and should I be worried? Whether CVE-2025-32387 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 CVE-2025-32387 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 CVE-2025-32387? Upgrade
helm.sh/helm/v3to 3.17.3 or later.