The TFTP server in Cisco IOS 12.2(44)SQ1 12.2(33)XN1 12.4(25e)JAM1 12.4(25e)JAO5m 12.4(23)JY 15.0(2)ED1 15.0(2)EY3 15.1(3)SVF4a and 15.2(2)JB1 and IOS XE 2.5.x 2.6.x 3.1.xS 3.2.xS 3.3.xS 3.4.xS and 3.5.xS before 3.6.0S; 3.1.xSG 3.2.xSG and 3.3.xSG before 3.4.0SG; 3.2.xSE before 3.3.0SE; 3.2.xXO before 3.3.0XO; 3.2.xSQ; 3.3.xSQ; and 3.4.xSQ allows remote attackers to cause a denial of service (device hang or reload) via multiple requests that trigger improper memory management aka Bug ID CSCts66733.