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

{
    "lastseen": "",
    "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.",
    "published": "2026-04-14T01:48:41.166Z",
    "modified": "2026-04-14T01:48:41.166Z",
    "type": "cve",
    "title": "External Secrets Operator has DNS exfiltration via getHostByName in its v2 template engine",
    "source": "GitHub_M",
    "references": "https://github.com/external-secrets/external-secrets/security/advisories/GHSA-r2pg-r6h7-crf3\nhttps://github.com/external-secrets/external-secrets/commit/6800989bdc12782ca2605d3b8bf7f2876a16551a\nhttps://github.com/external-secrets/external-secrets/releases/tag/v2.3.0",
    "id": "CVE-2026-34984",
    "bulletinFamily": "",
    "cwe": [
        "CWE-200"
    ],
    "cvelist": null,
    "sourceData": "external-secrets external-secrets < 2.3.0",
    "sourceHref": "",
    "cvss": {
        "score": 7.1,
        "severity": "HIGH",
        "vector": "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",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "external-secrets",
    "version": "< 2.3.0",
    "vendor": "external-secrets",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}