Out-of-bounds Read in Debevv Nanomodbus
CVE-2026-71256
nanoMODBUS through v1.23.0 contains an out-of-bounds stack read leading to a wild-pointer write in nmbs_read_device_identification_basic / recv_read_device_identification_res in nanomodbus.c. A fixed 3-element stack array order[3] = {0,1,2} maps object IDs to buffer indices. The server-supplied object_id field (0-255, read directly from the wire) is used without any bounds check as buf_index = order[object_id].
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.006 (46.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Debevv Nanomodbus — versions 0
Weakness classification (CWE)
References
- 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c (third-party-advisory)
- 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c (third-party-advisory)
Frequently asked questions
- What is CVE-2026-71256?
- CVE-2026-71256 is a critical-severity vulnerability in Debevv Nanomodbus, classified under Out-of-bounds Read. CVSS score: 9.8/10. Published 2026-08-05.
- How severe is CVE-2026-71256?
- Critical severity. CVSS v3 base score is 9.8 out of 10.