CVE-2026-34984

HIGH EPSS 17.6%
Published Apr 14, 20262mo ago · Modified Jun 17, 20262w ago
7.1 CVSS 4.0
High
Find Similar
Published Apr 14, 2026 2mo ago
Last Modified Jun 17, 2026 2w 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.

CVSS Details

Base Score
7.1
Exploitability
—
Impact
—
Vector string
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
17.6% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-200 Exposure of Sensitive Information to an Unauthorized Actor Information Exposure

Affected Products 1

VendorProductVersionRange
external-secretsexternal_secrets_operator* <2.3.0

References 3

  • github.com https://github.com/external-secrets/external-secrets/commit/6800989bdc12782ca2605d3b8bf7f2876a16551a
    Patch
  • github.com https://github.com/external-secrets/external-secrets/releases/tag/v2.3.0
    ProductRelease Notes
  • github.com https://github.com/external-secrets/external-secrets/security/advisories/GHSA-r2pg-r6h7-crf3
    Vendor Advisory

Remediation

  • github.com https://github.com/external-secrets/external-secrets/commit/6800989bdc12782ca2605d3b8bf7f2876a16551a
    Patch