CVE-2026-102720
A DHCP server, or anyone on the LAN who answers a DISCOVER first, can make the client read about a
kilobyte past the end of the received message.
The option walk keeps a pointer and an offset in step, and the only bound check uses the offset:
```c
/* addons/dhcp/nxd_dhcp_client.c:7538, 7572 */
while (i < length - 1)
```
A TLV option occupies size + 2 bytes. `data` is advanced by size + 2 in total, `i` by size + 1, so
the offset falls one byte behind the real read position for every option the walk skips. After
enough skipped options the check `i < length - 1` still holds while `data` is already past the end
Leer descripción completaMostrar menos
of the message, and the subsequent read of the type and length bytes comes from whatever follows.
A single OFFER carrying a long run of skippable options is enough:
```
ERROR: AddressSanitizer: heap-buffer-overflow
0x61b000000794 is located 164 bytes to the right of 1648-byte region
```
A well formed OFFER through the same path is handled normally, the client records the offer and
moves to REQUESTING, so the difference is the option layout rather than the harness.
The read runs in the DHCP client thread while the client is still unconfigured, so it happens on
every boot in reach of a hostile DHCP responder. The values read are used to configure the
interface, which is how the disclosed bytes become observable.
Advance `i` by size + 2, or derive the bound from `data` rather than keeping a second counter.
Detalles técnicos trazas, registros y código del informe original
{
...
size = *(++data); /* data moves 1: type -> length byte */
data += size + 1; /* data moves size + 1 more */
i += size + 1; /* i moves only size + 1 */
}
READ of size 1 at 0x61b000000794 thread T5
#0 _nx_dhcp_search_buffer addons/dhcp/nxd_dhcp_client.c:7541
#1 _nx_dhcp_get_option_value addons/dhcp/nxd_dhcp_client.c:7082CVSS
- Versión: 4.0
- Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- Puntuación base: 5.3
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.15%
- Percentil entre todas las CVEs puntuadas: 4
- Fecha de la puntuación: 5/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
🎯 Técnicas ATT&CK
Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.
- Explotación
T1210Exploitation of Remote Serviceslateral movement75 % - Impacto principal
T1005Data from Local Systemcollection70 % - Impacto secundario
T1057Process Discoverydiscovery45 %
Buffer overflow en cliente DHCP (CWE-125) tras DISCOVER/OFFER malicioso en LAN adyacente sin autenticación. Lectura de memoria fuera de límites en thread DHCP no configurado durante arranque; datos leídos observable al configurar interfaz.
Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.
🛡️ Mitigaciones ATT&CK que cubren estas técnicas
Tecnologías afectadas (1)
⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.
CWE
- CWE-125
Referencias
JSON original (NVD)
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{
"id": "CVE-2026-102720",
"cveTags": [],
"metrics": {
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-102720",
"role": "CISA Coordinator",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"version": "2.0.3",
"timestamp": "2026-09-29T18:36:33.534376Z"
}
}
],
"cvssMetricV40": [
{
"type": "Secondary",
"source": "emo@eclipse.org",
"cvssData": {
"Safety": "NOT_DEFINED",
"version": "4.0",
"Recovery": "NOT_DEFINED",
"baseScore": 5.3,
"Automatable": "NOT_DEFINED",
"attackVector": "ADJACENT",
"baseSeverity": "MEDIUM",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"exploitMaturity": "NOT_DEFINED",
"providerUrgency": "NOT_DEFINED",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"privilegesRequired": "NONE",
"subIntegrityImpact": "NONE",
"vulnIntegrityImpact": "NONE",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"vulnAvailabilityImpact": "LOW",
"availabilityRequirement": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"subConfidentialityImpact": "NONE",
"vulnConfidentialityImpact": "LOW",
"confidentialityRequirement": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"vulnerabilityResponseEffort": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED"
}
}
]
},
"affected": [
{
"source": "emo@eclipse.org",
"affectedData": [
{
"vendor": "Eclipse Foundation",
"product": "eclipse-threadx/netxduo",
"versions": [
{
"status": "affected",
"version": "0",
"versionType": "semver",
"lessThanOrEqual": "6.5.1"
}
],
"defaultStatus": "unaffected"
}
]
}
],
"published": "2026-09-29T18:17:11.377",
"references": [
{
"url": "https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-8hj5-p46x-5h28",
"source": "emo@eclipse.org"
}
],
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"type": "Secondary",
"source": "emo@eclipse.org",
"description": [
{
"lang": "en",
"value": "CWE-125"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "A DHCP server, or anyone on the LAN who answers a DISCOVER first, can make the client read about a\n\n\n\nkilobyte past the end of the received message.\n\n\n\nThe option walk keeps a pointer and an offset in step, and the only bound check uses the offset:\n\n\n\n```c\n\n\n\n/* addons/dhcp/nxd_dhcp_client.c:7538, 7572 */\n\n\n\nwhile (i < length - 1)\n\n\n\n{\n\n ...\n size = *(++data); /* data moves 1: type -> length byte */\n data += size + 1; /* data moves size + 1 more */\n i += size + 1; /* i moves only size + 1 */\n\n\n}\n\n\n\n```\n\n\n\nA TLV option occupies size + 2 bytes. `data` is advanced by size + 2 in total, `i` by size + 1, so\n\n\n\nthe offset falls one byte behind the real read position for every option the walk skips. After\n\n\n\nenough skipped options the check `i < length - 1` still holds while `data` is already past the end\n\n\n\nof the message, and the subsequent read of the type and length bytes comes from whatever follows.\n\n\n\nA single OFFER carrying a long run of skippable options is enough:\n\n\n\n```\n\n\n\nERROR: AddressSanitizer: heap-buffer-overflow\n\n\n\nREAD of size 1 at 0x61b000000794 thread T5\n\n #0 _nx_dhcp_search_buffer addons/dhcp/nxd_dhcp_client.c:7541\n #1 _nx_dhcp_get_option_value addons/dhcp/nxd_dhcp_client.c:7082\n\n\n0x61b000000794 is located 164 bytes to the right of 1648-byte region\n\n\n\n```\n\n\n\nA well formed OFFER through the same path is handled normally, the client records the offer and\n\n\n\nmoves to REQUESTING, so the difference is the option layout rather than the harness.\n\n\n\nThe read runs in the DHCP client thread while the client is still unconfigured, so it happens on\n\n\n\nevery boot in reach of a hostile DHCP responder. The values read are used to configure the\n\n\n\ninterface, which is how the disclosed bytes become observable.\n\n\n\nAdvance `i` by size + 2, or derive the bound from `data` rather than keeping a second counter."
}
],
"lastModified": "2026-09-29T19:17:21.203",
"sourceIdentifier": "emo@eclipse.org"
}