AUGUST 15, 2026
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Case File

CVE-2026-71263

CRITICAL · CVSS 9.1 EPSS 0.28% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-08-05 · Last synced 2026-08-15

CyberRota Analysis

AI-Generated

The vulnerability affects the LINUXTCP port of FreeModbus, where an off-by-one bounds check flaw allows an unauthenticated attacker to send a specially crafted Modbus TCP packet that overflows a static buffer. This can lead to potential arbitrary code execution or data corruption due to the overflow into adjacent memory. Organizations using FreeModbus on Linux should prioritize patching this critical vulnerability to mitigate the risk of exploitation.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-71263
Severity
CRITICAL
CVSS
9.1
EPSS
0.28%
Linux

Original NVD Description

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.