CVE-2026-34984 (GCVE-0-2026-34984)

Vulnerability from cvelistv5 – Published: 2026-04-14 01:48 – Updated: 2026-04-14 01:48
VLAI?
Title
External Secrets Operator has DNS exfiltration via getHostByName in its v2 template engine
Summary
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 ?
7.1 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
CWE
  • CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
Assigner
References
Impacted products
Vendor Product Version
external-secrets external-secrets Affected: < 2.3.0
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      "providerMetadata": {
        "dateUpdated": "2026-04-14T01:48:41.166Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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          "url": "https://github.com/external-secrets/external-secrets/releases/tag/v2.3.0"
        }
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      "source": {
        "advisory": "GHSA-r2pg-r6h7-crf3",
        "discovery": "UNKNOWN"
      },
      "title": "External Secrets Operator has DNS exfiltration via getHostByName in its v2 template engine"
    }
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    "cveId": "CVE-2026-34984",
    "datePublished": "2026-04-14T01:48:41.166Z",
    "dateReserved": "2026-03-31T19:38:31.617Z",
    "dateUpdated": "2026-04-14T01:48:41.166Z",
    "state": "PUBLISHED"
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  }
}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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