FKIE_CVE-2026-102721
Vulnerability from fkie_nvd - Published: 2026-09-29 18:17 - Updated: 2026-09-29 19:17
Severity
Summary
A TFTP server that answers with a short ERROR packet makes the client read up to 64 bytes past the
received datagram.
Each receive path checks only that the datagram is at least four bytes long (nxd_tftp_client.c:1229,
1521, 1984). When the opcode is NX_TFTP_CODE_ERROR the message string is copied with a loop whose
only limits are the destination buffer and a NUL byte:
```c
/* addons/tftp/nxd_tftp_client.c:1769 */
for (i = 0; (i < (sizeof(tftp_client_ptr -> nx_tftp_client_error_string) - 1)) && (*buffer_ptr); i++)
```
Nothing compares `buffer_ptr` against `nx_packet_append_ptr`. An ERROR packet that carries no
terminating NUL, which a server controls completely, walks the loop off the end of the packet until
it happens to meet a zero byte or fills the 64 byte destination.
```
ERROR: AddressSanitizer: heap-buffer-overflow
READ of size 1 at 0x60d0000000c8 thread T4
#0 _nxd_tftp_client_file_read addons/tftp/nxd_tftp_client.c:1769
0x60d0000000c8 is 0 bytes to the right of 136-byte region
```
The open path has the same loop at :1327 and reports the same way. What is read lands in
`nx_tftp_client_error_string`, which the application is expected to display or log, so adjacent
packet pool memory ends up in whatever the device does with the error text.
Add `(buffer_ptr < packet_ptr -> nx_packet_append_ptr)` to the loop condition in all three paths.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"packageName": "NetX Duo",
"product": "NetX Duo",
"vendor": "Eclipse Foundation",
"versions": [
{
"lessThanOrEqual": "6.5.1",
"status": "affected",
"version": "0",
"versionType": "semver"
}
]
}
],
"source": "emo@eclipse.org"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "A TFTP server that answers with a short ERROR packet makes the client read up to 64 bytes past the\n\n\n\nreceived datagram.\n\n\n\nEach receive path checks only that the datagram is at least four bytes long (nxd_tftp_client.c:1229,\n\n\n\n1521, 1984). When the opcode is NX_TFTP_CODE_ERROR the message string is copied with a loop whose\n\n\n\nonly limits are the destination buffer and a NUL byte:\n\n\n\n```c\n\n\n\n/* addons/tftp/nxd_tftp_client.c:1769 */\n\n\n\nfor (i = 0; (i \u003c (sizeof(tftp_client_ptr -\u003e nx_tftp_client_error_string) - 1)) \u0026\u0026 (*buffer_ptr); i++)\n\n\n\n```\n\n\n\nNothing compares `buffer_ptr` against `nx_packet_append_ptr`. An ERROR packet that carries no\n\n\n\nterminating NUL, which a server controls completely, walks the loop off the end of the packet until\n\n\n\nit happens to meet a zero byte or fills the 64 byte destination.\n\n\n\n```\n\n\n\nERROR: AddressSanitizer: heap-buffer-overflow\n\n\n\nREAD of size 1 at 0x60d0000000c8 thread T4\n\n #0 _nxd_tftp_client_file_read addons/tftp/nxd_tftp_client.c:1769\n\n\n0x60d0000000c8 is 0 bytes to the right of 136-byte region\n\n\n\n```\n\n\n\nThe open path has the same loop at :1327 and reports the same way. What is read lands in\n\n\n\n`nx_tftp_client_error_string`, which the application is expected to display or log, so adjacent\n\n\n\npacket pool memory ends up in whatever the device does with the error text.\n\n\n\nAdd `(buffer_ptr \u003c packet_ptr -\u003e nx_packet_append_ptr)` to the loop condition in all three paths."
}
],
"id": "CVE-2026-102721",
"lastModified": "2026-09-29T19:17:21.417",
"metrics": {
"cvssMetricV40": [
{
"cvssData": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"availabilityRequirement": "NOT_DEFINED",
"baseScore": 6.9,
"baseSeverity": "MEDIUM",
"confidentialityRequirement": "NOT_DEFINED",
"exploitMaturity": "NOT_DEFINED",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/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",
"version": "4.0",
"vulnAvailabilityImpact": "LOW",
"vulnConfidentialityImpact": "LOW",
"vulnIntegrityImpact": "NONE",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"source": "emo@eclipse.org",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-102721",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-29T18:35:29.043788Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-09-29T18:17:11.540",
"references": [
{
"source": "emo@eclipse.org",
"url": "https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-wvc9-5m9h-rvxc"
}
],
"sourceIdentifier": "emo@eclipse.org",
"vulnStatus": "Awaiting Analysis",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-125"
}
],
"source": "emo@eclipse.org",
"type": "Secondary"
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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