Roaring Penguin » Pppoe : Security Vulnerabilities, CVEs,

Roaring Penguin pppoe (rp-ppoe), if installed or configured to run setuid root contrary to its design, allows local users to overwrite arbitrary files. NOTE: the developer has publicly disputed the claim that this is a vulnerability because pppoe "is NOT designed to run setuid-root." Therefore this identifier applies *only* to those configurations and installations under which pppoe is run setuid root despite the developer's warnings.

rp-pppoe PPPoE client allows remote attackers to cause a denial of service via the Clamp MSS option and a TCP packet with a zero-length TCP option.