Capsule CVE-2026-61672

Requires (1) an authenticated Capsule tenant owner (PR:L), and (2) a cluster administrator forbidden list configured such that case-insensitive sorting and byte-order sorting of the denied metadata keys produce different orderings - i.e., a list mixing capitalized and lowercase keys. Uniformly lowercase forbidden lists whose two orderings coincide are NOT exploitable. The bypass targets namespace, Service, or delegated node metadata restrictions on Capsule versions prior to 0.13.7. The dependence on a specific mixed-case administrator configuration (AC:H) is the primary limiting factor, alongside the requirement for valid tenant-owner credentials.

This is a genuine but conditional authorization-bypass issue, not a high-CVSS-low-real-risk inflation. The CVSS 3.1 vector (AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:H/A:N = 7.1) is internally consistent with the mechanism: network-reachable Kubernetes API, but AC:H because exploitation depends on the administrator's forbidden list containing keys whose case-insensitive ordering diverges from byte ordering (mixed capitalized/lowercase keys) - uniformly-lowercase lists are explicitly not affected. PR:L reflects an authenticated tenant owner; S:C and I:H reflect that a successful bypass reaches beyond the tenant boundary to influence cluster policies, network exposure, and scheduling. No EPSS score, no CISA KEV listing, and no public exploit code are provided in the input, so exploitation status is 'no public exploit identified at time of analysis.' The dominant risk-limiting signal is the AC:H precondition (misconfigured/mixed-case forbidden list) plus required tenant-owner authentication, which makes this an environment-specific rather than mass-exploitable flaw. Note the input tag 'Information Disclosure' conflicts with the vector, which is integrity-dominant (I:H, C:L) - this is a policy/authorization bypass, not primarily disclosure.

In a cluster where the administrator's Capsule forbidden metadata list mixes capitalized and lowercase keys, an authenticated tenant owner submits a namespace, Service, or node metadata key that the case-insensitive-sorted-but-byte-searched binary lookup fails to find. api.ValidateForbidden incorrectly allows the key, letting the tenant set restricted metadata that influences cluster policy, network exposure, or scheduling outside its tenant boundary. No public exploit code is identified in the provided data.