External-Secrets: >> External Secrets Operator >> 0.20.4 Security Vulnerabilities
External Secrets Operator reads information from a third-party service and automatically injects the values as Kubernetes Secrets. Versions 2.2.0 and below contain a vulnerability in runtime/template/v2/template.go where the v2 template engine removes env and expandenv from Sprig's TxtFuncMap() but leaves the getHostByName function accessible to user-controlled templates. Since ESO executes templates within the controller process, an attacker who can create or update templated ExternalSecret resources can invoke controller-side DNS lookups using secret-derived values. This creates a DNS exfiltration primitive, allowing fetched secret material to be leaked via DNS queries without requiring direct outbound network access from the attacker's workload. The impact is a confidentiality issue, particularly in environments where untrusted or lower-trust users can author templated ExternalSecret resources and the controller has DNS resolution capability. This issue has been fixed in version 2.3.0.
CVSS Score
7.1
EPSS Score
0.0
Published
2026-04-14
External Secrets Operator reads information from a third-party service and automatically injects the values as Kubernetes Secrets. Starting in version 0.20.2 and prior to version 1.2.0, the `getSecretKey` template function, while introduced for senhasegura Devops Secrets Management (DSM) provider, has the ability to fetch secrets cross-namespaces with the roleBinding of the external-secrets controller, bypassing our security mechanisms. This function was completely removed in version 1.2.0, as everything done with that templating function can be done in a different way while respecting External Secrets Operator's safeguards As a workaround, use a policy engine such as Kubernetes, Kyverno, Kubewarden, or OPA to prevent the usage of `getSecretKey` in any ExternalSecret resource.
CVSS Score
9.3
EPSS Score
0.0
Published
2026-01-21