The PPP Access Concentrator (PPPAC) on SEIL SEIL/x86 routers 1.00 through 3.10, SEIL/X1 routers 1.00 through 4.50, SEIL/X2 routers 1.00 through 4.50, SEIL/B1 routers 1.00 through 4.50, SEIL/Turbo routers 1.80 through 2.17, and SEIL/neu 2FE Plus routers 1.80 through 2.17 allows remote attackers to cause a denial of service (session termination or concentrator outage) via a crafted TCP packet.