EUVD-2026-45380
GHSA-3x22-r5w3-j249
Severity by source
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Primary rating from Vendor (VulnCheck) · only source for this CVE.
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
3DescriptionCVE.org
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.
AnalysisAI
Denial of service and heap corruption in OpenPLC_v3 lets an authenticated web-interface user overflow the 100-byte MB_device.dev_name buffer via an oversized device_name field on the /modbus endpoint. Because getData() in modbus_master.cpp copies delimiter-bounded characters with no bounds check, a ~200-byte value writes 100 bytes past the allocation, overwriting adjacent Modbus config fields (protocol, dev_address, ip_port) and crashing the PLC control loop. No public exploit identified at time of analysis, though VulnCheck published a detailed technical advisory; the affected repository is archived and no vendor-released patch was identified.
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Same weakness CWE-122 – Heap-based Buffer Overflow
View allSame technique Heap Overflow
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External POC / Exploit Code
Leaving vuln.today