CVE-2021-21363: Generator Web Application: Local Privilege Escalation Vulnerability via System Temp Directory

Severity: high (CVSS 7.0 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: 2021-03-11 · updated 2026-06-17
Weakness: CWE-378

Description

swagger-codegen is an open-source project which contains a template-driven engine to generate documentation, API clients and server stubs in different languages by parsing your OpenAPI / Swagger definition. In swagger-codegen before version 2.4.19, on Unix like systems, the system's temporary directory is shared between all users on that system. A collocated user can observe the process of creating a temporary sub directory in the shared temporary directory and race to complete the creation of the temporary subdirectory. This vulnerability is local privilege escalation because the contents of the `outputFolder` can be appended to by an attacker. As such, code written to this directory, when executed can be attacker controlled. For more details refer to the referenced GitHub Security Advisory. This vulnerability is fixed in version 2.4.19. Note this is a distinct vulnerability from CVE-2021-21364.

Affected products

swagger-api swagger-codegen: before 2.4.19 — fixed in 2.4.19

How to fix

Upgrade to a fixed version: swagger-api swagger-codegen 2.4.19. Check the vendor advisory for mitigations.

References

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