CVE-2026-34984: Github.com/external secrets/external secrets External Secrets Operator Has DNS-based Vulnerability
HIGHCVE-2026-34984 is a HIGH (CVSS 6.5) external secrets operator has dns-based vulnerability (CWE-200: Exposure of Sensitive Information to an Unauthorized Actor) affecting Github.com/external secrets/external secrets libraries in the Go ecosystem. The issue involves external secrets operator has dns-based secret exfiltration via gethostbyname in external secrets v2 template engine. Remediation is available by upgrading affected packages to version 1.3.3-0.20260331202714-6800989bdc12.
CVE-2026-34984 at a Glance
Security Impact
CVSS: 6.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N).
How to Fix CVE-2026-34984
To remediate this vulnerability, upgrade all affected Github.com/external secrets/external secrets dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade github.com/external-secrets/external-secrets to 1.3.3-0.20260331202714-6800989bdc12Upgrade github.com/external-secrets/external-secrets to Latest secure releaseRun the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for github.com/external-secrets/external-secretsHow to Check if You Are Affected
To determine whether your application is affected by CVE-2026-34984, inspect your project dependencies for Github.com/external secrets/external secrets:
inspect dependencies for github.com/external-secrets/external-secretsAnalyze the terminal output to locate any version of Github.com/external secrets/external secrets in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.3.3-0.20260331202714-6800989bdc12), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor, where the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. In Github.com/external secrets/external secrets, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-34984 Affected Github.com/external secrets/external secrets Versions
2 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
github.com/external-secrets/external-secrets
|
Go |
< 1.3.3-0.20260331202714-6800989bdc12
|
1.3.3-0.20260331202714-6800989bdc12
|
|
github.com/external-secrets/external-secrets
|
Go |
≥ 2.0.0
≤ 2.2.0
|
|
References
Frequently Asked Questions
What is CVE-2026-34984?
Which Github.com/external secrets/external secrets versions are affected?
What version fixes CVE-2026-34984?
Is github.com/external-secrets/external-secrets affected?
What is the CVSS score of CVE-2026-34984?
What CWE is associated with CVE-2026-34984?
How can I check Go dependencies for CVE-2026-34984?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-r2pg-r6h7-crf3",
"modified" : "2026-04-28T04:20:16Z",
"published" : "2026-04-13T16:36:36Z",
"aliases" : [ "CVE-2026-34984" ],
"summary" : "External Secrets Operator has DNS-based secret exfiltration via getHostByName in External Secrets v2 template engine",
"details" : "## Summary\n\nThe v2 template engine in `runtime/template/v2/template.go` imports Sprig’s `TxtFuncMap()` and removes `env` and `expandenv`, but leaves `getHostByName` available to user-controlled templates. Because ESO executes templates inside the controller process, an attacker who can create or update templated ExternalSecret resources can trigger controller-side DNS lookups using secret-derived values, creating a DNS exfiltration primitive.\n\n### Impact\nThis is a confidentiality issue. In environments where untrusted or lower-trust users can author templated ExternalSecret resources and the controller can perform DNS resolution, fetched secret material can be exfiltrated through DNS without requiring direct outbound access from the attacker’s workload.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N"
}, {
"type" : "CVSS_V4",
"score" : "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"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/external-secrets/external-secrets"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "1.3.3-0.20260331202714-6800989bdc12"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "github.com/external-secrets/external-secrets"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "2.0.0"
}, {
"last_affected" : "2.2.0"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/external-secrets/external-secrets/security/advisories/GHSA-r2pg-r6h7-crf3"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-34984"
}, {
"type" : "WEB",
"url" : "https://github.com/external-secrets/external-secrets/commit/6800989bdc12782ca2605d3b8bf7f2876a16551a"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/external-secrets/external-secrets"
}, {
"type" : "WEB",
"url" : "https://github.com/external-secrets/external-secrets/releases/tag/v2.3.0"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-200" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2026-04-13T16:36:36Z",
"nvd_published_at" : "2026-04-14T03:16:08Z"
}
}