{"id":"CVE-2026-102721","published":"2026-09-29T18:17:11.540","lastModified":"2026-09-29T19:17:21.417","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.","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":["CWE-125"],"vendors":[],"products":[],"references":[{"url":"https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-wvc9-5m9h-rvxc","tags":[]}],"exploitRefs":[{"url":"https://github.com/eclipse-threadx/netxduo/security/advisories/GHSA-wvc9-5m9h-rvxc","tags":[]}],"hasPoc":true,"ai":null}