Vulnerability in Jenkins Templating Engine Plugin (CVE-2021-21646)

Summary

Vulnerability in Jenkins Templating Engine Plugin (CVE-2021-21646). Successful exploitation can lead to full system takeover.

Original description

The description as published by the source.

Jenkins Templating Engine Plugin 2.1 and earlier does not protect its pipeline configurations using Script Security Plugin, allowing attackers with Job/Configure permission to execute arbitrary code in the context of the Jenkins controller JVM.

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-2021-21646 has been found in Jenkins Templating Engine Plugin.
Successful exploitation can lead to full system takeover.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Jenkins Templating Engine Plugin CVE-2021-21646" on the vendor's site.

CVE-2021-21646 (Jenkins Templating Engine Plugin)
Attack vector: remote (network-reachable) / no user interaction
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.

❓ What is the problem

A vulnerability (unclassified) exists in Jenkins Templating Engine Plugin.

📍 Affected scope

Check the vendor advisory for the affected versions of Jenkins Templating Engine Plugin.

🔥 Severity

Severity: ?. Successful exploitation can lead to full system takeover.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

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

1
Identify exposure identify
```
Audit SBOM/dependencies for affected components.
```
資産台帳・SBOM・依存マニフェストで Jenkins Templating Engine Plugin を使っているサービスとバージョンを洗い出す。
2
Post-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。

References

advisory openwall.com
advisory jenkins.io