src/main/java/org/keycloak/protocol/cas/endpoints/AbstractValidateEndpoint.java

@@ -98,7 +98,7 @@
            throw new CASValidationException(CASErrorCode.INVALID_TICKET_SPEC, "Malformed service ticket", Response.Status.BAD_REQUEST);
        }

        String ticketValue = ticket.substring(prefix.length()); 
        String ticketValue = ticket.substring(prefix.length());

        boolean isReusable = ticket.startsWith(CASLoginProtocol.PROXY_GRANTING_TICKET_PREFIX);
        // Check if the ticket is hex encoded or using old method