CVE-2026-71254CWE-787

CVE-2026-71254

Critical · published August 5, 2026

CVSS v3.1
9.8
EPSS
1%
Percentile
45.4
In the wild
Unconfirmed
What it is

nanoMODBUS through v1.23.0 contains an out-of-bounds write in the Modbus server-side handle_read_file_record function (FC 0x14, Read File Record) in nanomodbus.c. The function validates that the total request size does not exceed 245 bytes and that each sub-request's record_length is at most 124, but it never validates the CUMULATIVE response size across all sub-requests before processing them.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00553 · 45.4th percentile
Weakness
CWE-787 · Out-of-bounds Write
Published
2026-08-05T16:18Z
References (2)
https://github.com/debevv/nanoMODBUS · 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2chttps://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c · 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
EPSS history
Timeline
  • 05 AUG 11:44Z
    nanoMODBUS Server-Side Out-of-Bounds Write in handle_read_file_record()
    cvelistv5