Privilege Escalation in org.openapitools:openapi-generator-online (CVE-2021-21428)
Summary
Vulnerability in org.openapitools:openapi-generator-online (CVE-2021-21428). Successful exploitation can lead to full system takeover. Exploitable via File.createTempFile. Mitigation: upgrade to 5.1.0 or later.
Original description
The description as published by the source.
Impact
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.
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.
Vulnerable Code
This vulnerability exists due to a race condition between the deletion of the randomly generated temporary file and the creation of the temporary directory.
File outputFolder = File.createTempFile("codegen-", "-tmp"); // Attacker knows the full path of the file that will be generated
// delete the file that was created
outputFolder.delete(); // Attacker sees file is deleted and begins a race to create their own directory before the code generator
// and make a directory of the same name
// SECURITY VULNERABI…
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2021-21428 has been found in org.openapitools:openapi-generator-online.
Attackers can target a specific entry point like File.createTempFile over the network to misuse the product.
Successful exploitation can lead to full system takeover.
What to do: upgrade org.openapitools:openapi-generator-online to 5.1.0 or later.
If unsure, ask your IT team or search "org.openapitools:openapi-generator-online CVE-2021-21428" on the vendor's site.
CVE-2021-21428 (org.openapitools:openapi-generator-online) — CWE-269
Attack vector: local / unauthenticated / no user interaction
Attack surface: File.createTempFile / Files.createTempFile
Patched: 5.1.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-269) exists in org.openapitools:openapi-generator-online. Attackers reach the vulnerable code path via File.createTempFile without authentication.
Check the vendor advisory for the affected versions of org.openapitools:openapi-generator-online. Attack surface: File.createTempFile / Files.createTempFile.
Severity: ?. Successful exploitation can lead to full system takeover.
Update to 5.1.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで org.openapitools:openapi-generator-online を使っているサービスとバージョンを洗い出す。
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2Apply patch patch
Upgrade org.openapitools:openapi-generator-online to 5.1.0ステージング環境で 5.1.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com