CVE-2026-102721
TFTP client and server copy the ERROR packet message without bounding the read against the packet
Published Sep 29, 2026
CVSS 4.0 · 6.9 Medium
EPSS < 1%
KEV · Not listed
Description
In Eclipse ThreadX NetX Duo versions 6.0 through 6.5.2.202603a, the TFTP client copies the message of a received ERROR packet without bounding the copy by the end of the datagram, and the TFTP server reads one byte past a minimal ERROR packet. A malicious TFTP server can make the client copy up to 64 bytes of adjacent packet-pool memory into the error string the application retrieves, or fault on targets with memory protection.
Affected Products
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CVE record
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NVD configurations
No data
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Red Hat packages
No data
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OpenCVE enrichment
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||
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| Eclipse Foundation | Eclipse ThreadX NetX Duo | unaffected |
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| Vendor | Product | Versions | ||||||||
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| Eclipse | Netx Duo |
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Remediation
Tracking
Advisories
Metrics
Attack Vector Network
Attack Complexity Low
Privileges Required None
Attack Requirements None
User Interaction None
Vulnerable System Confidentiality Impact Low
Vulnerable System Integrity Impact None
Vulnerable System Availability Impact Low
Subsequent System Confidentiality Impact None
Subsequent System Integrity Impact None
Subsequent System Availability Impact None
No CVSS v3.1
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.253% probability within 30 days)
Exploitation none
Automatable yes
Technical Impact partial
References
History
Nov 4, 2026 9:45 AM
Description updated. Title updated
View changes
| 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. | In Eclipse ThreadX NetX Duo versions 6.0 through 6.5.2.202603a, the TFTP client copies the message of a received ERROR packet without bounding the copy by the end of the datagram, and the TFTP server reads one byte past a minimal ERROR packet. A malicious TFTP server can make the client copy up to 64 bytes of adjacent packet-pool memory into the error string the application retrieves, or fault on targets with memory protection. |
| Title | TFTP Client Buffer Overflow via Malformed ERROR Packet | TFTP client and server copy the ERROR packet message without bounding the read against the packet |
Sep 30, 2026 9:00 PM
First appearance in the feed. Affected vendors updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Eclipse
Eclipse netx Duo |
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| Vendors & Products |
Eclipse
Eclipse netx Duo |
Sep 29, 2026 10:15 PM
Title updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Title | TFTP Client Buffer Overflow via Malformed ERROR Packet |
Sep 29, 2026 7:30 PM
Scoring metrics updated
View changes
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
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Sep 29, 2026 6:00 PM
Description updated. Weaknesses updated. Added references. Scoring metrics updated
View changes
| 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 |
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| Metrics |
cvssV4_0
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Weaknesses
