In Contiki 3.0, Telnet option negotiation is mishandled. During negotiation between a server and a client, the server may fail to give the WILL/WONT or DO/DONT response for DO and WILL commands because of improper handling of exception condition, which leads to property violations and denial of service. Specifically, a server sometimes sends no response, because a fixed buffer space is available for all responses and that space may have been exhausted.

In Contiki 3.0, a buffer overflow in the Telnet service allows remote attackers to cause a denial of service because the ls command is mishandled when a directory has many files with long names.

In Contiki 3.0, a Telnet server that silently quits (before disconnection with clients) leads to connected clients entering an infinite loop and waiting forever, which may cause excessive CPU consumption.

In Contiki 3.0, potential nonterminating acknowledgment loops exist in the Telnet service. When the negotiated options are already disabled, servers still respond to DONT and WONT requests with WONT or DONT commands, which may lead to infinite acknowledgment loops, denial of service, and excessive CPU consumption.

An issue was discovered in Contiki through 3.0. When sending an ICMPv6 error message because of invalid extension header options in an incoming IPv6 packet, there is an attempt to remove the RPL extension headers. Because the packet length and the extension header length are unchecked (with respect to the available data) at this stage, and these variables are susceptible to integer underflow, it is possible to construct an invalid extension header that will cause memory corruption issues and lead to a Denial-of-Service condition. This is related to rpl-ext-header.c.

An issue was discovered in Contiki through 3.0 and Contiki-NG through 4.5. The code for parsing Type A domain name answers in ip64-dns64.c doesn't verify whether the address in the answer's length is sane. Therefore, when copying an address of an arbitrary length, a buffer overflow can occur. This bug can be exploited whenever NAT64 is enabled.

An issue was discovered in the IPv6 stack in Contiki through 3.0. There are inconsistent checks for IPv6 header extension lengths. This leads to Denial-of-Service and potential Remote Code Execution via a crafted ICMPv6 echo packet.

An issue was discovered in the IPv6 stack in Contiki through 3.0. There is an insufficient check for the IPv6 header length. This leads to Denial-of-Service and potential Remote Code Execution via a crafted ICMPv6 echo packet.

An issue was discovered in Contiki through 3.0. A memory corruption vulnerability exists in the uIP TCP/IP stack component when handling RPL extension headers of IPv6 network packets in rpl_remove_header in net/rpl/rpl-ext-header.c.

An issue was discovered in Contiki through 3.0. An infinite loop exists in the uIP TCP/IP stack component when processing IPv6 extension headers in ext_hdr_options_process in net/ipv6/uip6.c.