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.
Analysis
Analysis and contextual insights are available on OpenCVE Cloud.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Eclipse Foundation | NetX Duo | unaffected |
|
No data.
No data.
No data available yet.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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Tue, 29 Sep 2026 22:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Title | TFTP Client Buffer Overflow via Malformed ERROR Packet |
Tue, 29 Sep 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
Tue, 29 Sep 2026 18:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | 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. | |
| Weaknesses | CWE-125 | |
| References |
| |
| Metrics |
cvssV4_0
|
Subscriptions
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MITRE
Status: PUBLISHED
Assigner: eclipse
Published:
Updated: 2026-09-29T18:36:05.599Z
Reserved: 2026-09-29T16:15:17.020Z
Link: CVE-2026-102721
Vulnrichment
Updated: 2026-09-29T18:35:40.497Z
NVD
Status : Awaiting Analysis
Published: 2026-09-29T18:17:11.540
Modified: 2026-09-29T19:17:21.417
Link: CVE-2026-102721
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-09-29T22:00:08Z
-
CWE-125
Out-of-bounds Read