CVE-2026-71263CWE-787

CVE-2026-71263

Critical · published August 5, 2026

CVSS v3.1
9.1
EPSS
1%
Percentile
42.0
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.1 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00501 · 42.0th percentile
Weakness
CWE-787 · Out-of-bounds Write
Published
2026-08-05T17:24Z
References (2)
https://github.com/cwalter-at/freemodbus · 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2chttps://github.com/cwalter-at/freemodbus/blob/master/demo/LINUXTCP/port/porttcp.c · 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
EPSS history
Timeline
  • 05 AUG 12:26Z
    FreeModbus LINUXTCP Port Off-by-One Global Buffer Overflow in xMBPortTCPPool()
    cvelistv5