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.
References
Configurations
No configuration.
History
No history.
Information
Published : 2026-08-06 22:18
Updated : 2026-09-16 20:21
NVD link : CVE-2026-5855
Mitre link : CVE-2026-5855
CVE.ORG link : CVE-2026-5855
JSON object : View
Products Affected
No product.
CWE
CWE-125
Out-of-bounds Read