GHSA-qcxp-gm7m-4j5v: Quarkus: Authentication/Authorization Bypass via Advanced Path Normalization Vulnerabilities

Quarkus HTTP path-based authorization policies can be bypassed using encoded semicolons (%3B) to smuggle matrix parameters past the security layer, and using encoded slashes (%2F) or backslashes (%5C) to access protected static resources. This is a distinct issue from CVE-2026-39852, which addressed only literal semicolon stripping. Technical Details The security layer (AbstractPathMatchingHttpSecurityPolicy) normalizes request paths using Vert.x's normalizedPath(), which only decodes unreserved RFC 3986 characters (letters, digits, -, ., _, ~). It then strips matrix parameters by looking for literal ; characters. This creates two mismatches: 1. Encoded semicolons (%3B): Since %3B is not decoded by normalizedPath(), the matrix parameter stripping in pathWithoutMatrixParams() never sees it. The encoded semicolon and everything after it become part of the path segment, causing policy matching to fail. This affects all path-policy-protected endpoints. 2. Static resource path mismatch: Static resource handlers (StaticHandlerImpl, FileSystemStaticHandler) perform full percent-decoding via URIDecoder.decodeURIComponent() and backslash-to-slash conversion before filesystem resolution. Reserved characters like %2F (slash) and %5C (backslash) that survive the security layer's partial decoding are fully decoded before file serving. REST endpoints using Quarkus REST (RESTEasy Reactive) are not affected by the %2F/%5C vectors because the routing layer also uses normalizedPath() — both security and routing agree on the path, so no mismatch exists. Attack Vectors Encoded semicolon (matrix parameter smuggling), affects all path-policy-protected endpoints: - /api/admin%3Bbypass=true/data: security sees this as a single segment admin%3Bbypass=true, which does not match the /api/admin/* policy. The request passes through unauthenticated. - /api/secret%3b/data: same mechanism with lowercase hex digit. Encoded slash/backslash on static resources, affects static files behind