# CVE-2026-34984: External Secrets Operator has DNS exfiltration via getHostByName in its v2 template engine > Attackers can exfiltrate secret data via DNS queries by exploiting the getHostByName function in the External Secrets Operator template engine. - **Severity:** High 7.1 (`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`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 14 Apr 2026 - **Updated:** 14 Apr 2026 - **Also known as:** GHSA-r2pg-r6h7-crf3, GO-2026-5602, MINI-5c9j-974f-562w, MINI-xx2p-8qq7-9wfq ## What is CVE-2026-34984? CVE-2026-34984 is a high-severity vulnerability in external-secrets, published on 14 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim. ### Official 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. Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor) ## Which versions are affected by CVE-2026-34984? 5 open source packages ship an affected version, including github.com/external-secrets/external-secrets. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/external-secrets/external-secrets` | Go | All versions | 1.3.3-0.20260331202714-6800989bdc12 | | `github.com/external-secrets/external-secrets` | Go | All versions | 1.3.3-0.20260331202714-6800989bdc12 | | `github.com/external-secrets/external-secrets` | Go | All versions | 1.3.3-0.20260331202714-6800989bdc12 | | `github.com/external-secrets/external-secrets` | Go | From 2.0.0 to 2.2.0 | None | | `github.com/external-secrets/external-secrets` | Go | From 2.0.0 to 2.2.0 | None | Products: External-Secrets External Secrets Operator. ## How do I fix CVE-2026-34984? Upgrade github.com/external-secrets/external-secrets to 1.3.3-0.20260331202714-6800989bdc12 or later. ## Is CVE-2026-34984 being exploited? There is no known exploitation of CVE-2026-34984 in the wild and no public exploit code. ## Other vulnerabilities in external-secrets - [CVE-2024-36540](https://insights.sbomify.com/CVE-2024-36540/): Missing authorization in n/a (critical 9.8) - [CVE-2026-22822](https://insights.sbomify.com/CVE-2026-22822/): External Secrets Operator insecurely retrieves secrets through the getSecretKey templating function (critical 9.3) - [CVE-2024-45041](https://insights.sbomify.com/CVE-2024-45041/): External Secrets Operator vulnerable to privilege escalation (high 8.3) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-34984 and fix it if it is affected. What it is: CVE-2026-34984 is a high-severity vulnerability in external-secrets, published on 14 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-34984 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/external-secrets/external-secrets (Go): affected all versions; fixed in 1.3.3-0.20260331202714-6800989bdc12 - github.com/external-secrets/external-secrets (Go): affected all versions; fixed in 1.3.3-0.20260331202714-6800989bdc12 - github.com/external-secrets/external-secrets (Go): affected all versions; fixed in 1.3.3-0.20260331202714-6800989bdc12 - github.com/external-secrets/external-secrets (Go): affected from 2.0.0 up to 2.2.0; no fix listed - github.com/external-secrets/external-secrets (Go): affected from 2.0.0 up to 2.2.0; no fix listed Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-34984/ (Markdown: https://insights.sbomify.com/CVE-2026-34984/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34984 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34984 - OSV: https://osv.dev/vulnerability/CVE-2026-34984 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-34984/ Summaries are generated and may contain mistakes; the official description above is the record.