PatchTheCVECVE-2026-71255: nanoMODBUS through v1.23.0 contains an out-of-bounds write in the Modbus client-side recv_read_device_identifi
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HIGH 8.6REMOTE
CVE-2026-71255 is a high-severity flaw (CVSS 8.6) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
nanoMODBUS through v1.23.0 contains an out-of-bounds write in the Modbus client-side recv_read_device_identification_res function (FC 0x2B/MEI 0x0E, Read Device Identification) in nanomodbus.c. The server-supplied object_length field (0-246) is validated only against the remaining PDU size (res_size_left) and is never validated against the caller-supplied buffers_length parameter.
Why this priority
- High severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 8.6 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.4% (top 69%) |
| CISA exploited list | No |
| Weakness | CWE-787 |
| Published | 2026-08-05 |
| Last modified | 2026-10-23 |
Publisher (CNA): TuranSec
Timeline
- Published CVE record published
- Updated Record last modified
Exact fixes by distribution
Fedora 46 · kwin-zones · FIXED · 1.0.13-1.fc46 · FEDORA-2026-95888f332b · source
sudo dnf upgrade --advisory=FEDORA-2026-95888f332b
Fedora ELN · nginx-mod-brotli · FIXED · 1.0.0~rc-16.eln159 · FEDORA-2026-501a6a8273 · source
sudo dnf upgrade --advisory=FEDORA-2026-501a6a8273
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Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.