{"cve":"CVE-2025-27136","nvd":{"published":"2025-03-10T19:15:40.770","modified":"2026-06-17T09:03:04.770","status":"Deferred","description":"LocalS3 is an Amazon S3 mock service for testing and local development. Prior to version 1.21, 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. The attacker only needs to be able to send HTTP requests to the LocalS3 service to exploit this vulnerability.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:P","score":5.5},"cvss_v3":null,"cwes":["CWE-611"],"references":["https://github.com/Robothy/local-s3/commit/d6ed756ceb30c1eb9d4263321ac683d734f8836f","https://github.com/Robothy/local-s3/security/advisories/GHSA-g6wm-2v64-wq36"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:00:17.429720821+00:00"},"epss":{"cve":"CVE-2025-27136","score":0.00533,"percentile":0.45044,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-g6wm-2v64-wq36","url":"https://osv.dev/vulnerability/GHSA-g6wm-2v64-wq36","summary":"LocalS3 CreateBucketConfiguration Endpoint XML External Entity (XXE) Injection","modified":"2025-03-14T21:20:31.621835Z","packages":[{"ecosystem":"Maven","name":"io.github.robothy:local-s3-rest","purl":"pkg:maven/io.github.robothy/local-s3-rest","ranges":["<1.21"],"fixed":["1.21"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}