Bitnami sealed-secrets up to 0.38.4 Template Execution sealedsecret_expansion.go Unseal spec.template.data missing encryption

Summaryinfo

A vulnerability was found in Bitnami sealed-secrets up to 0.38.4. It has been classified as problematic. This affects the function Unseal of the file pkg/apis/sealedsecrets/v1alpha1/sealedsecret_expansion.go of the component Template Execution. The manipulation of the argument spec.template.data leads to missing encryption. This vulnerability is uniquely identified as CVE-2026-59341. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Bitnami sealed-secrets up to 0.38.4 and classified as problematic. This issue affects the function Unseal of the file pkg/apis/sealedsecrets/v1alpha1/sealedsecret_expansion.go of the component Template Execution. The manipulation of the argument spec.template.data with an unknown input leads to a missing encryption vulnerability. Using CWE to declare the problem leads to CWE-311. The product does not encrypt sensitive or critical information before storage or transmission. Impacted is confidentiality. The summary by CVE is:

A security vulnerability exists in the Sealed Secrets controller's unauthenticated POST endpoints. By submitting a modified payload containing custom Go template logic in spec.template.data, an attacker with internal network access can abuse the handler as a decryption oracle to recover the full plaintext of any sealed secret. The POST /v1/verify and /v1/rotate handlers call Unseal() to decrypt target secrets, then render any Go templates found in spec.template.data.* using the decrypted payload as the evaluation context (pkg/apis/sealedsecrets/v1alpha1/sealedsecret_expansion.go). Errors encountered during template execution are directly reflected in the resulting HTTP response status codes. Missing AEAD label binding: the spec.template.data field is omitted from the AEAD authenticated-data label binding ciphertext to metadata. As a result, an attacker can copy a target's valid metadata and encryptedData verbatim, satisfying AEAD decryption and label validation, while freely replacing spec.template.data with arbitrary template logic. Side-channel oracle: template execution errors map directly to HTTP response codes. HTTP 200 (OK) indicates template execution succeeded; HTTP 409 (Conflict) indicates template execution failed (e.g. via {{ fail "..." }}). By injecting conditional statements such as {{ if eq (substr 0 1 .password) "S" }}ok{{ else }}{{ fail "x" }}{{ end }}, an attacker receives an HTTP 200 status when a character guess is correct and an HTTP 409 when it is incorrect. This differential response leaks one character-equality bit per request, allowing full secret extraction over successive queries. Attack vector & prerequisites: unauthenticated; requires network access to the controller's internal service port (:8080). Although this service is not exposed to the public internet by default, it is accessible to any pod within the Kubernetes cluster or via a kubectl port-forward connection.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-59341 since 07/04/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1600 according to MITRE ATT&CK.

Upgrading to version 0.40.0 eliminates this vulnerability.

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Productinfo

Vendor

• Bitnami

Name

• sealed-secrets

Version

• 0.38.0
• 0.38.1
• 0.38.2
• 0.38.3
• 0.38.4

Website

• Product: https://github.com/bitnami/sealed-secrets/

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