OmniFaces: Forged combined-resource IDs and related output/push boundaries

## 1. Forged combined-resource IDs `CombinedResourceInfo` accepts a path-derived ID without an authenticity check, inflates it without an output limit, converts it to attacker-selected resource identifiers, and retains unique IDs in an unbounded static cache. In bounded tests, 20,754 encoded bytes inflated to 16,000,000 characters (about 770:1; about 49 MB observed heap delta), and 200 unique IDs added 200 permanent cache entries. A legitimately shaped short ID remained about 1:1, while malformed input was rejected; the missing distinction is between a server-issued ID and an attacker-minted but structurally valid ID. The minimal application also confirmed three sink tails from the same forged-ID root: - A wildcard CDN mapping performed a server-side fetch and relayed the exact loopback-canary body. This requires the documented combined-resource and wildcard-CDN configuration. - A forged inner `.xhtml` resource bypassed the excluded-resource boundary and returned its raw content. - A forged `omnifaces.graphic` inner resource plus a canary `Host` header caused an outbound GET to that host. This result is blind and deployment-dependent; I am not claiming arbitrary-scheme or arbitrary-destination SSRF. These behaviors reproduce after the fix for CVE-2026-41883 / GHSA-vp6r-9m58-5xv8. That advisory concerned EL evaluation order in the wildcard CDN path. This report has a different root: unsigned combined IDs and missing decode/cache bounds, with separately demonstrated residual sink behavior. ## 2. Source-map cache With the documented optional source-map handler above a synthetic resource handler, 40 unique missing combined-resource requests grew the process-wide source-map cache from 13 to 92 entries. It has no size or eviction bound. This has a separate cache, configuration prerequisite, and fix from family 1. ## 3. HashParam callback output A URL-fragment value containing a single-quote JavaScript payload was stored by `o:hashParam` and later written unescaped into the Ajax callback script. On the follow-up Ajax render, real Chrome executed the canary `window.__omniXss=1337`. This requires a page using `o:hashParam` and the follow-up Ajax render. ## 4. Session/view push-channel replay A fresh WebSocket client with no HTTP cookie connected using a victim's session-scoped channel ID and received the victim's subsequent push. The code checks application-wide ID existence but does not bind the handshake to the current HTTP session, despite the documented current-session guarantee. The UUID remains an unguessable bearer-token prerequisite; this is replay after token exposure, not brute force. ## 5. Push idle-connection and fanout behavior Twelve independent clients joined one application-scoped channel and all 12 received the same push. Current code sets every accepted session's maximum idle timeout to zero, retains sessions in an unbounded per-channel queue, and walks the full queue on each push. I am reporting the demonstrated mechanism as a bounded design weakness: container connection limits remain an outer bound, and I am not claiming unbounded heap growth from the 12-client test. ## Intentionally excluded leads - A duplicate-Range response-amplification lead was disproved. Twenty-four ranges produced only one response body because the stream wrapper closes after the first range. I am not reporting it as a security issue. - The older `Servlets.facesRedirect` XML issue is fixed on the current branch. I am not reporting it as a new current-upstream issue. ## Expected invariants - Only server-issued combined IDs should be accepted; decoding and caches should be bounded; excluded resources and dynamic handlers should not become attacker-selected inner resources. - Dynamic URLs should not derive an outbound destination from an untrusted `Host` header. - Source-map lookups should not create unbounded process-lifetime state. - `HashParam` values must be escaped for a JavaScript string inside an XML CDATA callback. - Session/view push subscriptions should be bound to the owning HTTP session or authenticated principal; idle limits and per-channel caps should remain operator-controllable. ## Suggested fixes and available evidence - Authenticate generated combined IDs with a per-deployment secret, cap inflated output, bound the combined cache, and avoid caching failed loads. - Require an existing/registered inner resource before wildcard remapping and reject excluded resource types at serve time. - Derive dynamic-resource origins from trusted configuration rather than the request `Host` value. - Bound or evict the source-map cache. - Apply JavaScript-string plus CDATA-safe encoding to `HashParam` callback values. - Capture and verify HTTP-session or principal ownership during the WebSocket handshake; retain a finite idle timeout and configurable per-channel limits. Daniel Birtwhistle