{"id":"GHSA-m49c-g9wr-hv6v","summary":"jinjava has Sandbox Bypass via JavaType-Based Deserialization","details":"### Summary\n\njinjava’s current sandbox restrictions prevent direct access to dangerous methods such as `getClass()`, and block instantiation of Class objects. However, these protections can be bypassed.\n\nBy using mapper.getTypeFactory().constructFromCanonical(), it is possible to instruct the underlying ObjectMapper to deserialize attacker-controlled input into arbitrary classes. This enables the creation of semi-arbitrary class instances without directly invoking restricted methods or class literals.\n\nAs a result, an attacker can escape the sandbox and instantiate classes such as java.net.URL, opening up the ability to access local files and URLs(e.g., file:///etc/passwd). With further chaining, this primitive can potentially lead to remote code execution (RCE).\n\n### Details\n\njinjava templates expose a built-in variable `____int3rpr3t3r____`, which provides direct access to the jinjavaInterpreter instance.\nThis variable was previously abused and protections were added to prevent call method from `JinjavaInterpreter` instances (see [Add interpreter to blacklist](https://github.com/HubSpot/jinjava/commit/1b9aaa4b420c58b4a301cf4b7d26207f1c8d1165)).\nHowever, interacting with the properties of `JinjavaInterpreter` instances remains [unrestricted](https://github.com/HubSpot/jinjava/blob/jinjava-2.8.0/src/main/java/com/hubspot/jinjava/el/ext/JinjavaBeanELResolver.java#L80-L84).\n\nFrom `____int3rpr3t3r____`, it is possible to traverse to the `config` field, which exposes an ObjectMapper. By invoking `readValue(String content, JavaType valueType)` on this ObjectMapper, an attacker can instantiate arbitrary classes specified via `JavaType`.\n\nAlthough jinjava explicitly restricts dangerous classes such as `Class`, `ClassLoader`, and so on inside `JinjavaBeanELResolver`, the `JavaType` class itself is [not restricted](https://github.com/HubSpot/jinjava/blob/jinjava-2.8.0/src/main/java/com/hubspot/jinjava/el/ext/JinjavaBeanELResolver.java#L246-L262). \n\nAs a result, an attacker can leverage `JavaType` construction (`constructFromCanonical`) to instantiate semi-arbitrary classes without directly calling restricted methods.\n\nThis allows sandbox escape and the creation of powerful primitives. \n\n### Impact\nEscape the Jinjava sandbox and instantiate a wide range of classes using JavaType.\nThis capability can be used to read arbitrary files and to perform full read SSRF by creating network-related objects.\nIn certain environments, depending on the available classes, this primitive can even lead to complete remote code execution.","aliases":["CVE-2025-59340"],"modified":"2026-07-31T22:30:11.344524827Z","published":"2025-09-17T19:56:21Z","database_specific":{"severity":"CRITICAL","github_reviewed":true,"github_reviewed_at":"2025-09-17T19:56:21Z","nvd_published_at":"2025-09-17T20:15:36Z","cwe_ids":["CWE-1336"]},"references":[{"type":"WEB","url":"https://github.com/HubSpot/jinjava/security/advisories/GHSA-m49c-g9wr-hv6v"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-59340"},{"type":"WEB","url":"https://github.com/github/advisory-database/pull/8141"},{"type":"WEB","url":"https://github.com/HubSpot/jinjava/commit/66df351e7e8ad71ca04dcacb4b65782af820b8b1"},{"type":"PACKAGE","url":"https://github.com/HubSpot/jinjava"},{"type":"WEB","url":"https://github.com/HubSpot/jinjava/releases/tag/jinjava-2.7.5"},{"type":"WEB","url":"https://github.com/HubSpot/jinjava/releases/tag/jinjava-2.8.1"}],"affected":[{"package":{"name":"com.hubspot.jinjava:jinjava","ecosystem":"Maven","purl":"pkg:maven/com.hubspot.jinjava/jinjava"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.8.0"},{"fixed":"2.8.1"}]}],"versions":["2.8.0"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/09/GHSA-m49c-g9wr-hv6v/GHSA-m49c-g9wr-hv6v.json"}},{"package":{"name":"com.hubspot.jinjava:jinjava","ecosystem":"Maven","purl":"pkg:maven/com.hubspot.jinjava/jinjava"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.7.0"},{"fixed":"2.7.5"}]}],"versions":["2.7.0","2.7.1","2.7.2","2.7.3","2.7.4"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/09/GHSA-m49c-g9wr-hv6v/GHSA-m49c-g9wr-hv6v.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}