Sealed Secrets: decryption oracle via Go template injection in unauthenticated controller endpoints
Summary
| CVE | CVE-2026-59341 |
|---|---|
| State | PUBLISHED |
| Assigner | vmware |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-15 10:17:05 UTC |
| Updated | 2026-09-15 18:17:26 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 4.2 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N
EPSS: 0.004030000 probability, percentile 0.339030000 (date 2026-09-15)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 4.2 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N |
| 3.1 | CNA | CVSS | 4.2 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
HighUser Interaction
RequiredScope
UnchangedConfidentiality
HighIntegrity
NoneAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:N/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Bitnami | Sealed-secrets | affected 0.38.4 semver | Not specified |
| CNA | Bitnami | Sealed-secrets | unaffected 0.40.0 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/bitnami/sealed-secrets | [email protected] | github.com | |
| github.com/bitnami/sealed-secrets/security/advisories/GHSA-qj4p-m373-p2wg | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.