{"cve":"CVE-2026-102721","nvd":{"published":"2026-09-29T18:17:11.540","modified":"2026-09-29T19:17:21.417","status":"Awaiting Analysis","description":"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 < (sizeof(tftp_client_ptr -> nx_tftp_client_error_string) - 1)) && (*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 < packet_ptr -> nx_packet_append_ptr)` to the loop condition in all three paths.","cvss_v4":{"vector":"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","score":6.9},"cvss_v3":null,"cwes":["CWE-125"],"references":["https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-wvc9-5m9h-rvxc"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:56:48.555445741+00:00"},"epss":{"cve":"CVE-2026-102721","score":0.00253,"percentile":0.16592,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}