What’s Vulnerable › Vulnerabilities

CVE-2021-21430: Creation of Temporary File in Directory with Insecure Permissions in auto-generated Java, Scala code

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-05-10 · updated 2026-06-17
• Weakness: CWE-269

Description

OpenAPI Generator allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec. Using `File.createTempFile` in JDK will result in creating and using insecure temporary files that can leave application and system data vulnerable to attacks. Auto-generated code (Java, Scala) that deals with uploading or downloading binary data through API endpoints will create insecure temporary files during the process. Affected generators: `java` (jersey2, okhttp-gson (default library)), `scala-finch`. The issue has been patched with `Files.createTempFile` and released in the v5.1.0 stable version.

Affected products

• OpenAPITools openapi-generator: before 5.1.1 — fixed in 5.1.1

How to fix

Upgrade to a fixed version: OpenAPITools openapi-generator 5.1.1. Check the vendor advisory for mitigations.

References

• https://github.com/OpenAPITools/openapi-generator/pull/8787
• https://github.com/OpenAPITools/openapi-generator/pull/8791
• https://github.com/OpenAPITools/openapi-generator/security/advisories/GHSA-cqxr-xf2w-943w
• https://github.com/OpenAPITools/openapi-generator/pull/8787
• https://github.com/OpenAPITools/openapi-generator/pull/8791
• https://github.com/OpenAPITools/openapi-generator/security/advisories/GHSA-cqxr-xf2w-943w

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