{"id":"CVE-2021-21430","aliases":["GHSA-cqxr-xf2w-943w"],"url":"https://o3.security/vulnerability/CVE-2021-21430","summary":"Creation of Temporary File in Directory with Insecure Permissions in auto-generated Java, Scala code","details":"### Impact\n\n**This vulnerability impacts generated code.** If this code was generated as a one-off occasion, not as a part of an automated CI/CD process, this code will remain vulnerable until fixed manually!\n\nOn Unix-Like systems, the system temporary directory is shared between all local users. When files/directories are created, the default `umask` settings for the process are respected. As a result, by default, most processes/apis will create files/directories with the permissions `-rw-r--r--` and `drwxr-xr-x` respectively, unless an API that explicitly sets safe file permissions is used.\n\nThis vulnerability exists due to the use of the JDK method `File.createTempFile`. This method creates an insecure temporary files that can leave application and system data vulnerable to exposure.\n\nAuto-generated code (Java, Scala) that deals with uploading or downloading binary data through API endpoints will create insecure temporary files during the process. For example, if the API endpoint returns a PDF file, the auto-generated clients will first download the PDF into a insecure temporary file that can be read by anyone on the system.\n\nAffected generators: \n - Java\n   - `okhttp-gson` (default library)\n     https://github.com/OpenAPITools/openapi-generator/blob/d85f61ff0cfd6b8cd7063a63f302998a51466269/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/ApiClient.mustache#L1085-L1088\n   - `jersey2`\n     https://github.com/OpenAPITools/openapi-generator/blob/d85f61ff0cfd6b8cd7063a63f302998a51466269/modules/openapi-generator/src/main/resources/Java/libraries/jersey2/ApiClient.mustache#L1035-L1038\n   - `resteasy`\n     https://github.com/OpenAPITools/openapi-generator/blob/d85f61ff0cfd6b8cd7063a63f302998a51466269/modules/openapi-generator/src/main/resources/Java/libraries/resteasy/ApiClient.mustache#L604-L607\n   - `retrofit2`\n      https://github.com/OpenAPITools/openapi-generator/blob/d85f61ff0cfd6b8cd7063a63f302998a51466269/modules/openapi-generator/src/main/resources/Java/libraries/retrofit2/play26/ApiClient.mustache#L202-L208\n - Scala\n   - `scala-finch`\n      https://github.com/OpenAPITools/openapi-generator/blob/764a3b044c19fadf4a0789473cde96a65b77868a/modules/openapi-generator/src/main/resources/scala-finch/api.mustache#L83-L88\n   - `scala-akka`\n      https://github.com/OpenAPITools/openapi-generator/blob/150e24dc553a8ea5230ffb938ed3e6020e972faa/modules/openapi-generator/src/main/resources/scala-akka-http-server/multipartDirectives.mustache#L71-L73\n\n### Patches\n\nThe issue has been patched by changing the generated code to use the JDK method `Files.createTempFile` and released in the v5.1.0 stable version.\n\nThis vulnerability has the same root cause as CVE-2021-21364 from the `swagger-api/swagger-codegen` project as this project and that one both share the same original source tree.\nhttps://github.com/swagger-api/swagger-codegen/security/advisories/GHSA-hpv8-9rq5-hq7w\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [OpenAPI Generator Github repo](https://github.com/openAPITools/openapi-generator/)\n* Email us at [security@openapitools.org](mailto:security@openapitools.org)","published":"2021-05-10T20:15:07.840Z","modified":"2026-10-20T10:55:20.220674974Z","cvss":{"score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":1,"affectedPackages":[{"ecosystem":"Maven","name":"org.openapitools:openapi-generator","fixedVersion":"5.1.0"}],"fix":{"url":"https://github.com/OpenAPITools/openapi-generator/pull/8787","label":"OpenAPITools/openapi-generator#8787"},"references":[{"type":"FIX","url":"https://github.com/OpenAPITools/openapi-generator/pull/8787"},{"type":"FIX","url":"https://github.com/OpenAPITools/openapi-generator/pull/8791"},{"type":"EVIDENCE","url":"https://github.com/OpenAPITools/openapi-generator/security/advisories/GHSA-cqxr-xf2w-943w"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21430"},{"type":"WEB","url":"https://github.com/OpenAPITools/openapi-generator/pull/9348"},{"type":"PACKAGE","url":"https://github.com/OpenAPITools/openapi-generator"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-20T10:55:20.220674974Z"}}