nanoMODBUS Client-Side Out-of-Bounds Write via object_length in recv_read_device_identification_res()
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA.
Summary
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 it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-71255
- 2026-10-03 Alias added: GHSA-9rfp-q4v5-653h
References
More debevv vulnerabilities
- TI-2026-49925 nanoMODBUS Client-Side Out-of-Bounds Read Leading to Wild-Pointer Write via object_id CVSS 3.1CRITICAL 9.8
- TI-2026-49923 nanoMODBUS Server-Side Out-of-Bounds Write in handle_read_file_record() CVSS 3.1CRITICAL 9.8
- TI-2026-39286 nanoMODBUS Off-by-One Buffer Overflow in recv_msg_header() via Crafted MBAP Length Field CVSS 4.0HIGH 7.8
Sources
- CVE-2026-71255 · CVE Program
- CVE-2026-71255 · NVD
- FIRST EPSS
- GHSA-9rfp-q4v5-653h · GitHub Advisory Database · CC BY 4.0
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