CVE-2026-54641

Summary A realm admin of tenant B can read the profile, client roles, and realm roles of any user in any other realm (including the master realm) by supplying the target user's UUID in the REST API path. Three read endpoints in UserResourceImpl check whether the caller holds the read:admin role but omit a check that the target user belongs to the caller's own realm. The vulnerability enables cross-tenant user enumeration and privilege-level reconnaissance. On a multi-tenant deployment the master realm administrator account is reachable from any tenant realm admin. Details The affected file is manager/src/main/java/org/openremote/manager/security/UserResourceImpl.java. Three methods are missing an authenticated-realm guard: get (line 102): public User get(RequestParams requestParams, String realm, String userId) { boolean hasAdminReadRole = hasResourceRole(ClientRole.READ_ADMIN.getValue(), Constants.KEYCLOAK_CLIENT_ID); if (!hasAdminReadRole && !Objects.equals(getUserId(), userId)) { throw new ForbiddenException("..."); } try { return identityService.getIdentityProvider().getUser(userId); } ... } The realm path parameter is accepted but never used. getUser(userId) delegates to getUserByIdFromDb(persistenceService, userId) which queries the database by UUID with no realm filter. getUserClientRoles (line 294): public String[] getUserClientRoles(RequestParams requestParams, String realm, String userId, String clientId) { boolean hasAdminReadRole = hasResourceRole(ClientRole.READ_ADMIN.getValue(), Constants.KEYCLOAK_CLIENT_ID); if (!hasAdminReadRole && !Objects.equals(getUserId(), userId)) { throw new ForbiddenException("..."); } try { return identityService.getIdentityProvider().getUserClientRoles(realm, userId, clientId); } ... } getUserRealmRoles (line 313): public String[] getUserRealmRoles(RequestParam

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