CVE-2026-71263
FreeModbus LINUXTCP Port Off-by-One Global Buffer Overflow in xMBPortTCPPool()
CVSS Score
9.1
EPSS Score
0.0%
EPSS Percentile
0th
The LINUXTCP port of FreeModbus contains an off-by-one bounds check in xMBPortTCPPool (demo/LINUXTCP/port/porttcp.c). The check uses a strict greater-than comparison instead of greater-than-or-equal against the 263-byte MB_TCP_BUF_SIZE limit.
| CWE | CWE-787 |
| Vendor | cwalter-at |
| Product | freemodbus |
| Published | Aug 5, 2026 |
| Last Updated | Aug 10, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High
Affected Versions
cwalter-at / FreeModbus
0 ≤ *
References
Credits
Alibek Baxtiyorov