CVE-2025-32387 is a medium-severity (CVSS 6.5) CWE-121 vulnerability in helm.sh/helm/v3. A fix is available for helm.sh/helm/v3 — see the affected versions and patch details below.
Helm Allows A Specially Crafted JSON Schema To Cause A Stack Overflow
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-32387.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-32387 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
helm.sh/helm/v3Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
A Helm contributor discovered that a specially crafted JSON Schema within a chart can lead to a stack overflow.
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.
Patches
This issue has been resolved in Helm v3.17.3.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | helm.sh/helm/v3 | all versions | 3.17.3go get helm.sh/helm/v3@v3.17.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for helm.sh/helm/v3, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update helm.sh/helm/v3 to 3.17.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-32387 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-32387 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-32387. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-32387 in your dependencies?
O3 Security finds CVE-2025-32387 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.