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    "cveMetadata": {
        "cveId": "CVE-2026-5855",
        "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "state": "PUBLISHED",
        "assignerShortName": "VulnCheck",
        "dateReserved": "2026-04-08T19:28:35.667Z",
        "datePublished": "2026-08-06T18:39:06.869Z",
        "dateUpdated": "2026-08-14T16:50:26.324Z"
    },
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                "shortName": "VulnCheck",
                "dateUpdated": "2026-08-14T16:50:26.324Z"
            },
            "title": "Contiki-NG LwM2M TLV Parser Out-of-Bounds Read via Unchecked Buffer Length in lwm2m_tlv_read",
            "datePublic": "2026-08-06T19:00:00.000Z",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "cweId": "CWE-125",
                            "description": "CWE-125 Out-of-bounds read",
                            "type": "CWE"
                        }
                    ]
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            ],
            "affected": [
                {
                    "vendor": "Contiki-NG",
                    "product": "Contiki-NG",
                    "versions": [
                        {
                            "status": "affected",
                            "version": "0",
                            "lessThan": "f1673b5766d4d4d514cefb8a0350f43653574997",
                            "versionType": "custom"
                        }
                    ],
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                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:contiki-ng:contiki-ng:*:*:*:*:*:*:*:*"
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                    ]
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            ],
            "descriptions": [
                {
                    "lang": "en",
                    "value": "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.",
                    "supportingMedia": [
                        {
                            "type": "text/html",
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                            "value": "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": [
                {
                    "url": "https://github.com/contiki-ng/contiki-ng",
                    "tags": [
                        "product"
                    ]
                },
                {
                    "url": "https://github.com/contiki-ng/contiki-ng/pull/3165",
                    "tags": [
                        "issue-tracking"
                    ]
                },
                {
                    "url": "https://github.com/contiki-ng/contiki-ng/commit/f1673b5766d4d4d514cefb8a0350f43653574997",
                    "tags": [
                        "patch"
                    ]
                }
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                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "scope": "UNCHANGED",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "NONE",
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                        "userInteraction": "NONE",
                        "vulnConfidentialityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "NONE",
                        "subIntegrityImpact": "NONE",
                        "vulnAvailabilityImpact": "HIGH",
                        "subAvailabilityImpact": "NONE",
                        "exploitMaturity": "NOT_DEFINED",
                        "Safety": "NOT_DEFINED",
                        "Automatable": "NOT_DEFINED",
                        "Recovery": "NOT_DEFINED",
                        "valueDensity": "NOT_DEFINED",
                        "vulnerabilityResponseEffort": "NOT_DEFINED",
                        "providerUrgency": "NOT_DEFINED",
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            "credits": [
                {
                    "lang": "en",
                    "value": "Kazuma Matsumoto, a security researcher at GMO Cybersecurity by IERAE, Inc.",
                    "type": "reporter"
                }
            ],
            "source": {
                "discovery": "UNKNOWN"
            },
            "x_generator": {
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        "adp": [
            {
                "metrics": [
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                            "content": {
                                "timestamp": "2026-08-07T16:19:49.994663Z",
                                "id": "CVE-2026-5855",
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                                "role": "CISA Coordinator",
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                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
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                    "dateUpdated": "2026-08-07T16:19:59.210Z"
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