CVE-2026-102713 Memory corruption in NetX Duo
Unauthenticated attackers can trigger heap overflows to disclose memory or cause denial of service in the NetX Duo TFTP server via oversized datagrams.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-102713?
CVE-2026-102713 is a high-severity memory corruption vulnerability in Eclipse Foundation NetX Duo, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The TFTP server accepts a DATA datagram of any size. The dispatcher rejects datagrams shorter than
four bytes (nxd_tftp_server.c:1037) and nothing anywhere checks an upper bound, in particular not
against the protocol maximum of 4 + NX_TFTP_FILE_TRANSFER_MAX. Two things follow from that one
missing check, both reachable before any authentication because TFTP has none.
The handler passes `nx_packet_length - 4` straight to FileX:
```c
/* addons/tftp/nxd_tftp_server.c:1863, 1889 */
status = nx_packet_copy(packet_ptr, &temp_ptr,
server_ptr -> nx_tftp_server_packet_pool_ptr, NX_WAIT_FOREVER);
...
fx_file_write(&(client_request_ptr -> nx_tftp_client_request_file),
packet_ptr -> nx_packet_prepend_ptr + 4, packet_ptr -> nx_packet_length - 4);
```
`nx_packet_length` is the length of a chain, not of one contiguous buffer, so FileX copies past the
end of the first packet:
```
ERROR: AddressSanitizer: heap-buffer-overflow
READ of size 1280 at 0x621000001108 thread T5
#0 __interceptor_memcpy #1 _fx_utility_memory_copy filex/common/src/fx_utility_memory_copy.c:78
0x621000001108 is 0 bytes to the right of 4104-byte region
```
Those bytes are written into the file the attacker is uploading, and a TFTP read request hands them
back, so this is a memory disclosure with a convenient retrieval channel.
The same datagram also wedges the server. `nx_packet_copy` at :1863 needs
ceil(nx_packet_length / pool_payload) packets and asks for them with NX_WAIT_FOREVER, so when the
attacker sizes the datagram beyond what the pool holds, the server thread suspends and never
returns. A liveness probe after one such datagram times out with the pool at 0 of 12 packets and
the server thread suspended, and no later client is served.
Reject `nx_packet_length > 4 + NX_TFTP_FILE_TRANSFER_MAX` in the DATA branch before either call,
and use a bounded wait rather than NX_WAIT_FOREVER for the copy.
Which versions are affected by CVE-2026-102713?
How do I fix CVE-2026-102713?
No fix has been published for CVE-2026-102713 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-102713 being exploited?
There is no known exploitation of CVE-2026-102713 in the wild and no public exploit code.
Sources
Also known as GHSA-fhxv-gc8j-2f6h, GHSA-wr79-332c-ff8f.