Contiki Ng

Contiki-NG's DNS/mDNS resolver skip_name() in os/services/resolv/resolv.c walks DNS wire-format name labels with no packet-boundary check, and the caller in newdata() invokes it in a loop iterating nquestions times from the attacker-controlled DNS header before validating the transaction ID. An attacker who sets nquestions higher than the number of complete questions present causes skip_name() to walk past the UDP packet buffer, and the returned pointer is cast to struct dns_answer * for further memory reads. On builds with RESOLV_CONF_SUPPORTS_MDNS enabled, any peer on the local segment can trigger the read unauthenticated via a multicast UDP 5353 packet with no outstanding query required; on standard DNS builds an attacker who can inject a UDP response from port 53 during an outstanding query can trigger the same read. Impact is out-of-bounds read of uip_buf and adjacent memory, disclosing memory contents or crashing the resolver.

Published: 2026-08-06T18:47:38.653Z
Updated: 2026-11-08T14:07:09.250Z

Contiki-NG's MQTT client parse_publish_vhdr() in os/net/app-layer/mqtt/mqtt.c sets topic_len_received=1 before checking topic_len against the 64-byte limit, so an over-length topic returns early but leaves the flag set. On the next TCP segment, tcp_input() re-invokes the parser with topic_received==0, and the persisted topic_len_received==1 skips the length-reading block containing the guard, falling through directly to a memcpy() that uses the unvalidated 16-bit topic_len as the copy length. The 65-byte topic[] destination overruns into adjacent struct fields including the payload_chunk pointer, which subsequent MQTT code dereferences, giving a compromised or attacker-controlled broker an arbitrary-pointer-write primitive. Contiki-NG's MQTT implementation has no TLS support so the connection is plaintext. Impact ranges from information disclosure and denial of service to remote code execution on embedded targets without memory protection.

Published: 2026-08-06T18:52:40.005Z
Updated: 2026-11-08T14:07:09.910Z

Contiki-NG's LwM2M TLV parser lwm2m_tlv_read() in os/services/lwm2m/lwm2m-tlv.c ignores its caller-supplied buffer length argument and reads up to six bytes from the input buffer with no bounds check. The caller in lwm2m-engine.c iterates while there is at least one byte remaining, so a crafted CoAP WRITE to any LwM2M endpoint whose final TLV supplies exactly one byte triggers up to five out-of-bounds reads of heap memory adjacent to the CoAP input buffer, disclosing memory contents (including key material and peer addresses) through the parsed tlv->id, tlv->length, and tlv->value fields. Corrupted tlv_len derived from the out-of-bounds memory further corrupts the caller's parse offset. In LwM2M NoSec mode, the default for constrained devices, no authentication is required.

Published: 2026-08-06T18:39:06.869Z
Updated: 2026-11-08T14:07:08.537Z

Contiki-NG is an open-source, cross-platform operating system for IoT devices. An unaligned memory access can be triggered in the two RPL implementations of the Contiki-NG operating system. The problem can occur when either one of these RPL implementations is enabled and connected to an RPL instance. If an IPv6 packet containing an odd number of padded bytes before the RPL option, it can cause the rpl_ext_header_hbh_update function to read a 16-bit integer from an odd address. The impact of this unaligned read is architecture-dependent, but can potentially cause the system to crash. The problem has not been patched as of release 4.9, but will be included in the next release. One can apply the changes in Contiki-NG pull request #2962 to patch the system or wait for the next release.

Published: 2024-11-27T18:20:41.583Z
Updated: 2024-11-27T19:20:07.764Z

Contiki-NG is an open-source, cross-platform operating system for IoT devices. An out-of-bounds read of 1 byte can be triggered when sending a packet to a device running the Contiki-NG operating system with SNMP enabled. The SNMP module is disabled in the default Contiki-NG configuration. The vulnerability exists in the os/net/app-layer/snmp/snmp-message.c module, where the snmp_message_decode function fails to check the boundary of the message buffer when reading a byte from it immediately after decoding an object identifier (OID). The problem has been patched in Contiki-NG pull request 2937. It will be included in the next release of Contiki-NG. Users are advised to either apply the patch manually or to wait for the next release. A workaround is to disable the SNMP module in the Contiki-NG build configuration.

Published: 2024-11-27T18:20:43.701Z
Updated: 2024-11-27T19:22:41.923Z