CVE-2026-32693: Unauthorized access to Kubernetes secrets in Juju

In Juju from version 3.0.0 through 3.6.18, the authorization of the "secret-set" tool is not performed correctly, which allows a grantee to update the secret content, and can lead to reading or updating other secrets. When the "secret-set" tool logs an error in an exploitation attempt, the secret is still updated contrary to expectations, and the new value is visible to both the owner and the grantee.