CVE-2026-34984 - External Secrets Operator has DNS exfiltration via getHostByName in its v2 template engine

CVE-2026-34984 - External Secrets Operator has DNS exfiltration via getHostByName in its v2 template engine

https://cvefeed.io/rssfeed/latest.atom / Tue, 04/14/2026 - 07:01
CVE ID :CVE-2026-34984
Published : April 14, 2026, 1:48 a.m. | 1 hour, 21 minutes ago
Description :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.
Severity: 0.0 | NA
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