GHSA-465p-v42x-3fmj Sealed Secrets for Kubernetes: Rotate API Allows Scope Widening from Strict/Namespace-Wide to Cluster-Wide via Untrusted Template Annotations

• Go github.com/bitnami-labs/sealed-secrets: < 0.36.0 → fixed in 0.36.0

This report shows a scope-widening issue in the rotate (re-encrypt) flow: the output scope can be derived from untrusted `spec.template.metadata.annotations` on the input sealed secret. If a victim sealed secret is strict- or namespace-scoped, an attacker who can submit it to the rotate endpoint can set `sealedsecrets.bitnami.com/cluster-wide=true` in the template metadata and receive a rotated sealed secret that is cluster-wide, enabling retargeting (`metadata.name`/`metadata.namespace`) and unsealing to recover the victim plaintext. Relevant Links (Pinned) • Rotate handler uses `NewSealedSecret(..., secret)` after unsealing: https://github.com/bitnami-labs/sealed-secrets/blob/946bc048f3407117c837da6e4300686522d4c4eb/pkg/controller/controller.go#L560-L606 • Scope derivation reads secret annotations (`SecretScope`): https://github.com/bitnami-labs/sealed-secrets/blob/946bc048f3407117c837da6e4300686522d4c4eb/pkg/apis/sealedsecrets/v1alpha1/sealedsecret_expansion.go#L112-L122 Root Cause The rotate flow unseals the input sealed secret to a `Secret`, then reseals using `NewSealedSecret(..., secret)`. Because `SecretScope(secret)` is computed from secret annotations, and unsealing applies `spec.template` metadata onto the unsealed secret, an attacker can influence the scope of the rotated output by mutating template annotations on the rotate input. Attack Path 1. Attacker obtains a victim `SealedSecret` object (for example via read access to resources or logs) and can submit it to the controller rotate endpoint. 2. Attacker sets `spec.template.metadata.annotations.sealedsecrets.bitnami.com/cluster-wide=true` (and optionally retargets name/namespace fields). 3. Rotate returns a resealed, cluster-wide sealed secret that is no longer bound to the victim name/namespace. 4. Attacker unseals the rotated output in their chosen namespace/name to recover the victim plaintext. Proof of Concept Setup + run: ```bash unzip poc.zip -d poc cd poc make test ``` Canonical output (excerpt): ``` [CALLSITE_HIT]: pkg/apis/sealedsecrets/v1alpha1/sealedsecret_expansion.go:112 SecretScope [PROOF_MARKER]: scope_widened=true rotated_scope=cluster-wide ``` Control output (excerpt): ``` [NC_MARKER]: scope_widened=false strict_scope_preserved=true ``` Fix Accepted When Rotate preserves the original sealing scope and does not allow scope widening based on untrusted template metadata; strict or namespace-wide inputs cannot produce cluster-wide outputs. poc.zip PR_DESCRIPTION.md attack_scenario.md