---
cve: "CVE-2026-71254"
severity: "CRITICAL"
cvss: 9.8
epss: "31%"
vendor: "debevv"
kev: false
exploited: false
published: "2026-08-05 12:18:57"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-18T20:43:22+02:00"
---

# CVE-2026-71254

> 9.8 CRITICAL · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- 91d6782930ee263bc760f27b0cbc5b82773c5f0d (Commit)

## Referenzen

- <https://github.com/debevv/nanoMODBUS>
- <https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-71254) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_