Generated Code Contains Local Information Disclosure Vulnerability (CVE-2021-21364)
Published Sources: CVE.org, OSV
What is affected, what to do
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.
Update Swagger-api Swagger-codegen to version 2.4.19.
- Affected
- Swagger-api Swagger-codegen
lt *..2.4.19
- Swagger-api Swagger-codegen
- Fixed in
- Swagger-api Swagger-codegen
2.4.19
- Swagger-api Swagger-codegen
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Metrics
5.5
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
5.3
CVSS v3
Severity Medium on the scale from 0 to 10.
Source: CVE.org, OSV
0.3 %
EPSS score
Low — model estimates < 1% exploitation likelihood.
Source: FIRST EPSS, percentile 20.8
Show all metrics
- Severity
- Medium
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 29.93 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 5.5 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 5.3
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 0.3 %
- Low — model estimates < 1% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 20.8
- Elevated — this CVE ranks above at least 10% of all CVEs scored today.
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-200, CWE-378, CWE-732
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
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 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.
Source: NVD (NIST), OSV (Open Source Vulnerabilities), cvelistv5
Affected products
The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.
| Affected versions | Fixed in | ||
|---|---|---|---|
| swagger-api | swagger-codegen |
|
|
| smartbear | swagger-codegen |
|
|
| maven | io.swagger:swagger-codegen |
|
|
Vendors and products
Weakness classes (CWE)
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
Class
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
Entry at MITRE CWE-200CWE-378Creation of Temporary File With Insecure Permissions
Base
Opening temporary files without appropriate measures or controls can leave the file, its contents and any function that it impacts vulnerable to attack.
Entry at MITRE CWE-378CWE-732Incorrect Permission Assignment for Critical Resource
Class
The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.
Entry at MITRE CWE-732
References & sources
- github.comswagger-api/swagger-codegen/security/advisories/GHSA-hpv8-9rq5-…web, x_refsource_CONFIRM, Mitigation, Third-party advisory
- NVD (NIST)vuln/detail/CVE-2021-21364advisory
- github.comswagger-api/swagger-codegen/commit/35adbd552d5f99b3ff1e0e59da22…web, x_refsource_MISC, Patch, Third-party advisory
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<a href="https://intel.neosec.eu/en/cve/CVE-2021-21364"><img src="https://intel.neosec.eu/badge/cve/CVE-2021-21364.svg?lang=en" alt="CVE-2021-21364 – NEOSEC Intel" height="20"></a>