CVE-2026-71263

CriticalCVSS 9.1

Published: 05/08/2026(UTC)Updated: 10/08/2026(UTC)Translated: 10/08/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.32%

24th percentile - higher than 24% of all known CVEs

Summary

In the LINUXTCP port of FreeModbus, there is 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.

Risk Assessment

The flaw can lead to out-of-bounds write, potentially causing system crash or arbitrary code execution by an attacker.

Recommendation

Fix the bounds check condition to >= to prevent out-of-buffer access. Also, conduct security testing to detect similar issues.

Original NVD description (English source)

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.