GHSA-g6wm-2v64-wq36 — local-s3-rest
Fix: Robothy/local-s3@d6ed756GHSA-g6wm-2v64-wq36 is a XML External Entity (XXE) vulnerability in io.github.robothy:local-s3-rest. A fix is available for io.github.robothy:local-s3-rest — see the affected versions and patch details below.
LocalS3 CreateBucketConfiguration Endpoint XML External Entity (XXE) Injection
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for GHSA-g6wm-2v64-wq36.
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.
Real-World Exposure
io.github.robothy:local-s3-restReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
Description
The LocalS3 service's bucket creation endpoint is vulnerable to XML External Entity (XXE) injection. When processing the CreateBucketConfiguration XML document during bucket creation, the service's XML parser is configured to resolve external entities. This allows an attacker to declare an external entity that references an internal URL, which the server will then attempt to fetch when parsing the XML.
The vulnerability specifically occurs in the location constraint processing, where the XML parser resolves external entities without proper validation or restrictions. When the external entity is resolved, the server makes an HTTP request to the specified URL and includes the response content in the parsed XML document.
This vulnerability can be exploited to perform server-side request forgery (SSRF) attacks, allowing an attacker to make requests to internal services or resources that should not be accessible from external networks. The server will include the responses from these internal requests in the resulting bucket configuration, effectively leaking sensitive information.
Steps to Reproduce
- Create an XML document that includes an external entity declaration pointing to the internal target:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE test [ <!ENTITY xxe SYSTEM "http://internal-web/flag.txt"> ]>
<CreateBucketConfiguration>
<LocationConstraint>&xxe;</LocationConstraint>
</CreateBucketConfiguration>
- Send a PUT request to create a new bucket with this configuration:
curl -X PUT http://app/test-bucket-2 -H 'Content-Type: application/xml' -d @payload.xml
- Retrieve the bucket location to see the resolved entity content:
curl http://app/test-bucket-2/?location
When these steps are executed, the server processes the XML, resolves the external entity by making a request to the internal URL, and includes the response in the bucket's location constraint. The attacker can then retrieve this information through the bucket location endpoint.
Mitigations
- Disable XML external entity resolution in the XML parser configuration. Most XML parsers have options to disable external entity processing.
- Implement proper input validation for XML documents, rejecting those that contain DOCTYPE declarations or external entity references.
- Use XML parsers that are configured securely by default and don't process external entities.
- If external entity processing is required, implement a whitelist of allowed URLs and validate all URLs before making any requests.
Impact
The vulnerability allows unauthenticated attackers to make the server perform HTTP requests to internal networks and services, potentially exposing sensitive information or enabling further attacks against internal systems. The attacker only needs to be able to send HTTP requests to the LocalS3 service to exploit this vulnerability.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.github.robothy:local-s3-rest | all versions | 1.21io.github.robothy:local-s3-rest:1.21 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.github.robothy:local-s3-rest, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update io.github.robothy:local-s3-rest to 1.21 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g6wm-2v64-wq36 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 GHSA-g6wm-2v64-wq36 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-g6wm-2v64-wq36. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-g6wm-2v64-wq36 in your dependencies?
O3 Security finds GHSA-g6wm-2v64-wq36 across Maven dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.