EUVD-2026-54226

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...

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

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

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...

Astra Linux – Vulnerability in open-iscsi

A issue was discovered in Contiki through version 3.0. An integer overflow exists in the uIP TCP/IP stack component when parsing TCP MSS options for IPv4 network packets in the uipprocess function in net/ipv4/uip.c...

Astra Linux – Vulnerability in open-iscsi

A issue was discovered in Contiki version 3.0. A out-of-bounds read vulnerability exists in the uIP TCP/IP stack component when calculating checksums for IP packets in the upperlayerchksum function in net/ipv4/uip.c...

CVE-2021-28362

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 respec...

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...