{"id":"CVE-2025-59340","aliases":["GHSA-m49c-g9wr-hv6v"],"url":"https://o3.security/vulnerability/CVE-2025-59340","summary":"jinjava 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.","published":"2025-09-17T20:01:55.788Z","modified":"2026-08-12T03:51:25.416261493Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Maven","name":"com.hubspot.jinjava:jinjava","fixedVersion":"2.8.1"},{"ecosystem":"Maven","name":"com.hubspot.jinjava:jinjava","fixedVersion":"2.7.5"}],"fix":{"url":"https://github.com/HubSpot/jinjava/commit/66df351e7e8ad71ca04dcacb4b65782af820b8b1","label":"HubSpot/jinjava@66df351"},"references":[{"type":"WEB","url":"https://github.com/HubSpot/jinjava/releases/tag/jinjava-2.8.1"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/59xxx/CVE-2025-59340.json"},{"type":"ADVISORY","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":"FIX","url":"https://github.com/HubSpot/jinjava/commit/66df351e7e8ad71ca04dcacb4b65782af820b8b1"},{"type":"WEB","url":"https://github.com/github/advisory-database/pull/8141"},{"type":"PACKAGE","url":"https://github.com/HubSpot/jinjava"},{"type":"WEB","url":"https://github.com/HubSpot/jinjava/releases/tag/jinjava-2.7.5"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:25.416261493Z"}}