CVE-2021-21430

Local data disclosure via insecure temporary files

Published May 10, 2021 · Updated Aug 3, 2024

Insecure temporary files in generated Java and Scala code before 5.1.0 allow local users to read binary API-transfer data. Affected generator templates call File.createTempFile, which honors permissive default umasks in shared temporary directories instead of creating owner-only files. Exploitation requires a collocated user on a Unix-like host while generated client or server code stages uploaded or downloaded binary content.

CVSS severity6.2
Medium
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Insecure temporary files in generated Java and Scala code before 5.1.0 allow local users to read binary API-transfer data. Affected generator templates call File.createTempFile, which honors permissive default umasks in shared temporary directories instead of creating owner-only files. Exploitation requires a collocated user on a Unix-like host while generated client or server code stages uploaded or downloaded binary content.

The record

CVE
CVE-2021-21430
Published
May 10, 2021
Updated
Aug 3, 2024
Vendor
OpenAPI Tools
Product
OpenAPI Generator
Classifications
CWE-379, T1005
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 10, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 5.1.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

OpenAPI Tools · OpenAPI Generatorversion=< 5.1.0

Published CVSS scores

6.2GitHubCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-379Creation of Temporary File in Directory with Insecure Permissions
T1005Data from Local System

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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