CVE-2026-11826 (GCVE-0-2026-11826)

Vulnerability from cvelistv5 – Published: 2026-07-18 13:35 – Updated: 2026-07-28 01:48
VLAI
Title
OpenPLC_v3 Heap-Based Buffer Overflow in Modbus Master getData()
Summary
OpenPLC_v3 contains a heap-based buffer overflow in the getData() function in webserver/core/modbus_master.cpp. getData() reads characters between two delimiters into a caller-supplied buffer with no size parameter and no bounds check. In parseConfig() the function is invoked with the 100-byte heap-allocated MB_device.dev_name field. An authenticated attacker with access to the OpenPLC web interface can send a crafted HTTP POST to the /modbus endpoint with an oversized device_name value; the value is persisted to mbconfig.cfg and parsed on load, overflowing dev_name and overwriting adjacent struct fields (protocol at offset 108, dev_address at offset 109, ip_port at offset 210). A 200-byte payload writes 100 bytes past the allocation. The result is heap corruption leading to runtime crash and denial of service of the PLC process control loop, with attacker-controlled overwrite of adjacent configuration fields. The upstream repository was archived on 2026-04-04 and no fix is expected; the vendor has confirmed the issue does not affect OpenPLC Runtime v4.
Severity
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-20 17:02 UTC
CWE
  • CWE-122 - Heap-based Buffer Overflow
Assigner
VulnCheck CNA under the mitre root
CNA scorecard B 84/100 over 5802 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
openplcproject OpenPLC_v3 Affected: 0 , ≤ b470206 (git)
    cpe:2.3:h:openplcproject:openplc_v3:*:*:*:*:*:*:*:*
Create a notification for this product.
Date Public
2026-07-17 00:00
Credits
Shuhratbek Uraimov Shuhratbek Uraimov
Show details on NVD website
To clipboard 

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