The official w3m project is unmaintained and has several vulnerabilities.

CVE-2016-9422 CVE-2016-9423 CVE-2016-9424 CVE-2016-9425 CVE-2016-9426
CVE-2016-9427 CVE-2016-9428 CVE-2016-9429 CVE-2016-9430 CVE-2016-9431
CVE-2016-9432 CVE-2016-9433 CVE-2016-9434 CVE-2016-9435 CVE-2016-9436
CVE-2016-9437 CVE-2016-9438 CVE-2016-9439 CVE-2016-9440 CVE-2016-9441
CVE-2016-9442 CVE-2016-9443

CVE-2016-9621 CVE-2016-9622 CVE-2016-9623 CVE-2016-9624 CVE-2016-9625
CVE-2016-9626 CVE-2016-9627 CVE-2016-9628 CVE-2016-9629 CVE-2016-9630
CVE-2016-9631 CVE-2016-9632 CVE-2016-9633