CVE-2023-34101
HighCVSS 7.3Exploitation Probability (EPSS)
Low risk39th percentile - higher than 39% of all known CVEs
Summary
Contiki-NG is an operating system for IoT devices. In version 4.8 and prior, when processing ICMP DAO packets in the `dao_input_storing` function, the system does not verify that the packet buffer is large enough, which can lead to out-of-bounds reads.
Risk Assessment
An attacker can exploit this vulnerability to read data outside the allocated buffer, potentially leading to unexpected system behavior or exposure of sensitive information.
Recommendation
It is recommended to upgrade to version 4.9 of Contiki-NG, where the issue has been patched. Alternatively, one can apply the changes from pull request #2435 to patch the system.
Other vulnerabilities in Contiki-NG
See all- CVE-2026-5857High
Contiki-NG's MQTT client in 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, the parser skips the length-reading block and performs a memcpy with an unvalidated length, leading to overflow of the topic[] buffer and overwriting adjacent fields, including the payload_chunk pointer. This can enable remote code execution on devices without memory protection.
- CVE-2026-5856High
Contiki-NG's DNS/mDNS resolver in skip_name() in os/services/resolv/resolv.c walks DNS wire-format name labels with no packet-boundary check, and the caller in newdata() iterates nquestions times from the attacker-controlled DNS header before validating the transaction ID. An attacker can set nquestions higher than the number of complete questions, causing out-of-bounds reads past the UDP packet buffer and disclosing memory contents or crashing the resolver.
- CVE-2026-5855High
Contiki-NG's LwM2M TLV parser in 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. A crafted CoAP WRITE with a final TLV supplying exactly one byte triggers up to five out-of-bounds reads of heap memory, disclosing memory contents (including key material and peer addresses) through the parsed tlv->id, tlv->length, and tlv->value fields. In LwM2M NoSec mode, the default for constrained devices, no authentication is required.
- CVE-2023-34100High
Contiki-NG, an operating system for IoT devices, has a vulnerability that allows reading data out of bounds of the IPv6 buffer when processing the MSS option in TCP packets. The issue involves buffer indexing in the module os/net/ipv6/uip6.c, which may lead to unauthorized memory access.
Original NVD description (English source)
Contiki-NG is an operating system for internet of things devices. In version 4.8 and prior, when processing ICMP DAO packets in the `dao_input_storing` function, the Contiki-NG OS does not verify that the packet buffer is big enough to contain the bytes it needs before accessing them. Up to 16 bytes can be read out of bounds in the `dao_input_storing` function. An attacker can truncate an ICMP packet so that it does not contain enough data, leading to an out-of-bounds read on these lines. The problem has been patched in the "develop" branch of Contiki-NG, and is expected to be included in release 4.9. As a workaround, one can apply the changes in Contiki-NG pull request #2435 to patch the system.