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

Medium 5.3 Published 11 Mar 2021 Updated 3 Aug 2024

Local attackers can exploit a race condition in temporary directory creation to inject malicious code into generated files, leading to privilege escalation.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: A user has to click or open something
Fix: Available

What is CVE-2021-21363?

CVE-2021-21363 is a medium-severity vulnerability in swagger-api swagger-codegen, published on 11 Mar 2021. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

Official 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.

Weakness: CWE-379, CWE-378

Which versions are affected by CVE-2021-21363?

2 open source packages ship an affected version, including io.swagger:swagger-codegen. It affects 1 product.

Package	Affected	Fixed in
`io.swagger:swagger-codegen` Maven	All versions	`2.4.19`
`io.swagger:swagger-codegen` Maven	All versions	`2.4.19`

Products include Smartbear Swagger-Codegen.

How do I fix CVE-2021-21363?

Upgrade io.swagger:swagger-codegen to 2.4.19 or later.

Is CVE-2021-21363 being exploited?

There is no known exploitation of CVE-2021-21363 in the wild and no public exploit code.

CVE-2021-21364 Generated Code Contains Local Information Disclosure Vulnerability Medium 5.3

Sources

Also known as GHSA-pc22-3g76-gm6j.