CVE-2021-21363

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account, but needs a user to act. High risk of data tampering.

Exploit odds

0.4% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-03-11 03:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:35 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.4% in the next 30 days (EPSS).
• Severity: 5.3 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-03-11 03:15 UTC

Last modified

2026-06-17 03:35 UTC

Exploit probability

0.4% · EPSS, next 30 days

Weakness

CWE-378

Record status

Modified

Affected

• Smartbear swagger-codegen < 2.4.19

Attack profile CVSS 3.1 · 5.3

Attack vector

Local

Complexity

High

Privileges needed

Low

User interaction

Required

Scope

Changed

Confidentiality

None

Integrity

High

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-21363.md and follow it. Check whether this project is affected by CVE-2021-21363. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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