by Kastro
Paper/Archive/CVE-2026-71254

CVE-2026-71254

debevv nanoMODBUS — nanoMODBUS Server-Side Out-of-Bounds Write in handle_read_file_record()

EPSS 0.6%CVSS 9.8
critical.is priorityof 100
39
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 46.2.462 × 209.2No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
nanoMODBUS≤ 1.23.0–CNA

Scores by source

TuranSec (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

writeupgithub.com/debevv/nanoMODBUSwriteupgithub.com/debevv/nanoMODBUS/blob/master/nanomodbus.c