CVE-2026-102721A TFTP server that answers with a short ERROR packet makes the client read up to 64 bytes past the received datagram.
Updated under an hour ago ()
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It affects Eclipse Foundation NetX Duo. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 6.9 MEDIUM (v4.0, CNA)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
- Weakness (CWE)
- CWE-125
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- eclipse
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 29, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Eclipse Foundation NetX Duo eclipse_foundation:netx_duo (from the name) | through 6.5.1 | CNA record |
References
- https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-wvc9-5m9h-rvxc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.