What is CVE-2021-21364?

CVE-2021-21364 is a medium-severity vulnerability in Smartbear Swagger-Codegen, classified under Information Disclosure. CVSS score: 5.3/10. Published 2021-03-11.

How severe is CVE-2021-21364?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Is CVE-2021-21364 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Information disclosure in Smartbear Swagger-Codegen

CVE-2021-21364

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 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. Because this vulnerability impacts generated code, the generated code will remain vulnerable until fixed manually! This vulnerability is fixed in version 2.4.19. Note this is a distinct vulnerability from CVE-2021-21363.

Vulnerability class: Information Disclosure

Published 2021-03-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.003 (18.6th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 19th percentile — 18.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Smartbear Swagger-Codegen
Swagger-Api Swagger-Codegen — versions < 2.4.19

Weakness classification (CWE)

Public proof-of-concept exploits

ARPSyndicate/cvemon

References

github.com/swagger-api/swagger-codegen/security/advisories/GHSA-hpv8-9rq5-hq7w (Third Party Advisory, Mitigation)
github.com/swagger-api/swagger-codegen/commit/35adbd552d5f99b3ff1e0e59da228becc… (Patch, Third Party Advisory)

Frequently asked questions

What is CVE-2021-21364?: CVE-2021-21364 is a medium-severity vulnerability in Smartbear Swagger-Codegen, classified under Information Disclosure. CVSS score: 5.3/10. Published 2021-03-11.
How severe is CVE-2021-21364?: Medium severity. CVSS v3 base score is 5.3 out of 10.
Is CVE-2021-21364 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.