EUVD-2026-54225

Contiki-NG's DNS/mDNS resolver skipname 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 attack...

CVE-2026-5855

Contiki-NG's LwM2M TLV parser lwm2mtlvread 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...

CVE-2026-5857

Contiki-NG's MQTT client parsepublishvhdr in os/net/app-layer/mqtt/mqtt.c sets topiclenreceived=1 before checking topiclen against the 64-byte limit, so an over-length topic returns early but leaves the flag set. On the next TCP segment, tcpinput re-invokes the parser with topicreceived==0, and t...

CVE-2026-5856

Contiki-NG's DNS/mDNS resolver skipname 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 attack...

CVE-2026-5857

The CVE-2026-5857 entry documents a bug in Contiki-NG’s MQTT client, where parse_publish_vhdr() sets topic_len_received=1 before validating topic_len against the 64-byte limit. On the next TCP segment, a persisted flag causes the parser to bypass the guard and perform a memcpy() using an unvalida...

CVE-2026-5857 Contiki-NG MQTT Client Out-of-Bounds Write in PUBLISH Topic Parser via Persistent State Between TCP Segments

Contiki-NG's MQTT client parsepublishvhdr in os/net/app-layer/mqtt/mqtt.c sets topiclenreceived=1 before checking topiclen against the 64-byte limit, so an over-length topic returns early but leaves the flag set. On the next TCP segment, tcpinput re-invokes the parser with topicreceived==0, and t...

CVE-2026-5857 Contiki-NG MQTT Client Out-of-Bounds Write in PUBLISH Topic Parser via Persistent State Between TCP Segments

Contiki-NG's MQTT client parsepublishvhdr in os/net/app-layer/mqtt/mqtt.c sets topiclenreceived=1 before checking topiclen against the 64-byte limit, so an over-length topic returns early but leaves the flag set. On the next TCP segment, tcpinput re-invokes the parser with topicreceived==0, and t...

CVE-2026-5857 Contiki-NG MQTT Client Out-of-Bounds Write in PUBLISH Topic Parser via Persistent State Between TCP Segments

Contiki-NG's MQTT client parsepublishvhdr in os/net/app-layer/mqtt/mqtt.c sets topiclenreceived=1 before checking topiclen against the 64-byte limit, so an over-length topic returns early but leaves the flag set. On the next TCP segment, tcpinput re-invokes the parser with topicreceived==0, and t...

CVE-2026-5856 Contiki-NG DNS/mDNS Resolver Out-of-Bounds Read via Unchecked skip_name Traversal Before Transaction-ID Validation

Contiki-NG's DNS/mDNS resolver skipname 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 attack...

CVE-2026-5856 Contiki-NG DNS/mDNS Resolver Out-of-Bounds Read via Unchecked skip_name Traversal Before Transaction-ID Validation

Contiki-NG's DNS/mDNS resolver skipname 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 attack...

CVE-2026-5856

Affected software/component: Contiki-NG DNS/mDNS resolver (os/services/resolv/resolv.c). Root cause: skip_name() walks DNS wire-format labels without a packet-boundary check; newdata() loops nquestions from attacker-controlled DNS header before validating the transaction ID, causing the function ...

CVE-2026-5855

Contiki-NG: LwM2M TLV parser in os/services/lwm2m/lwm2m-tlv.c (function lwm2m_tlv_read) ignores the caller’s buffer length and may read up to six bytes without bounds checks. The engine loop continues while bytes remain, so a crafted CoAP WRITE to any LwM2M endpoint whose final TLV supplies exact...

CVE-2026-5855 Contiki-NG LwM2M TLV Parser Out-of-Bounds Read via Unchecked Buffer Length in lwm2m_tlv_read

Contiki-NG's LwM2M TLV parser lwm2mtlvread 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...

CVE-2026-5855 Contiki-NG LwM2M TLV Parser Out-of-Bounds Read via Unchecked Buffer Length in lwm2m_tlv_read

Contiki-NG's LwM2M TLV parser lwm2mtlvread 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...

CVE-2020-12141

An out-of-bounds read in the SNMP stack in Contiki-NG 4.4 and earlier allows an attacker to cause a denial of service and potentially disclose information via crafted SNMP packets to snmpberdecodestringlenbuffer in os/net/app-layer/snmp/snmp-ber.c...

CVE-2020-12140

A buffer overflow in os/net/mac/ble/ble-l2cap.c in the BLE stack in Contiki-NG 4.4 and earlier allows an attacker to execute arbitrary code via malicious L2CAP frames...

CVE-2020-24335

An issue was discovered in uIP through 1.0, as used in Contiki and Contiki-NG. Domain name parsing lacks bounds checks, allowing an attacker to corrupt memory with crafted DNS packets...

CVE-2023-50926

Contiki-NG is an open-source, cross-platform operating system for Next-Generation IoT devices. An out-of-bounds read can be caused by an incoming DIO message when using the RPL-Lite implementation in the Contiki-NG operating system. More specifically, the prefix information of the DIO message...

CVE-2023-50927

Contiki-NG is an open-source, cross-platform operating system for Next-Generation IoT devices. An attacker can trigger out-of-bounds reads in the RPL-Lite implementation of the RPL protocol in the Contiki-NG operating system. This vulnerability is caused by insufficient control of the lengths for...

CVE-2024-41125

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...