CVE-2021-21428

CRITICALNVD 9.39.3—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.3 under NVD CVSS v3. EPSS exploit probability: 0.4%, top 72% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Trending — 3 sources updated this week
9.3
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Openapi generator is a java tool which allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec. openapi-generator-online creates insecure temporary folders with File.createTempFile during the code generation process. The insecure temporary folders store the auto-generated files which can be read and appended to by any users on the system. The issue has been patched with Files.createTempFile and released in the v5.1.0 stable version.

CVSS v3
9.3
EG Score
9.3(medium)
EG Risk
46(Track)
EG Risk 46/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity93% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
27.6%
KEV
Not listed

Published

May 10, 2021

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated Jul 16, 2026
Patch available. Sources: github_pr, github.
github Patch Available

OpenAPI-Generator online generator: Local Privilege Escalation Vulnerability via System Temp Directory · Advisory · OpenAPITools/openapi-generator · GitHub

https://github.com/OpenAPITools/openapi-generator/security/advisories/GHSA-23x4-m842-fmwf
github_pr Patch Available

[online] use Files.createTempFile to address security concerns

Patch available: OpenAPITools/openapi-generator v6.3.0 (PR #8788 merged 2021-02-23)

https://github.com/OpenAPITools/openapi-generator/pull/8788

Affected Packages

(1 across 1 ecosystem)
Maven(1)
PackageVulnerable rangeFixed inDependents
org.openapitools:openapi-generator-online3.0.0 ... 5.0.1 (38 versions)5.1.0—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 49× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 103 total refreshes for this CVE.

  1. 2026-07-23 01:57 UTCEG score recompute
  2. 2026-07-22 22:43 UTCEG score recompute
  3. 2026-07-22 14:05 UTCEPSS rescore
  4. 2026-07-21 15:22 UTCEPSS rescore
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  9. 2026-07-18 20:59 UTCOSV refresh
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  1. 2026-07-06 02:21 UTCEPSS rescore
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  9. 2026-07-01 03:48 UTCOSV refresh
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  40. 2026-06-13 06:43 UTCOSV refresh
  41. 2026-06-12 23:10 UTCEPSS rescore
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  51. 2026-06-06 13:46 UTCEPSS rescore
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  72. 2026-05-26 16:51 UTCEG score recompute
  73. 2026-05-26 13:42 UTCEPSS rescore
  74. 2026-05-26 13:42 UTCEPSS rescore
  75. 2026-05-26 07:17 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-21428?
CVE-2021-21428 is a critical vulnerability published on May 10, 2021. Openapi generator is a java tool which allows generation of API client libraries (SDK generation), server stubs, documentation and configuration automatically given an OpenAPI Spec. openapi-generator-online creates insecure temporary folders with File.createTempFile during the code generation…
When was CVE-2021-21428 disclosed?
CVE-2021-21428 was first published in the National Vulnerability Database on May 10, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-21428 actively exploited?
CVE-2021-21428 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 27.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2021-21428?
CVE-2021-21428 has a CVSS v3 base score of 9.3 (NVD).
How do I remediate CVE-2021-21428?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-21428, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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