A flaw was found in Candlepin. The central authorization filter incorrectly grants access when any one of multiple @Verify-annotated parameters is accessible, instead of requiring access to every verified entity. A low-privilege authenticated attacker who can access the first referenced object can bypass authorization checks on subsequent objects. When target resource identifiers are known, this can enable unauthorized disclosure of consumer information and unauthorized modification of entitlements and related subscription resources, including across organizations.
Exploitation requires knowledge of target resource identifiers (consumer UUIDs, entitlement IDs, pool IDs, or certificate serials), which are not normally visible across organizations. Restrict Candlepin REST API access to trusted administrators where feasible until a fixed candlepin build is deployed. Limit which principals can obtain consumer client certificates or manage activation keys.