---
id: "CVE-2026-116014"
kind: "vulnerability"
aliases: ["CVE-2026-116014"]
title: "open62541: integer overflow in OPC UA client datatype parsing enables heap overflow"
severity: "critical"
cvss: 9.2
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["c", "embedded", "industrial-control", "infrastructure", "opc-ua", "open62541"]
not_affected_if: ["no-remote-datatype-fetch", "trusted-servers-only", "version-1.5.7-or-later"]
published_at: "2026-10-24T12:16:57+00:00"
first_seen_at: "2026-10-24T12:47:58+00:00"
updated_at: "2026-10-25T02:59:49+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-116014", "first_seen_at": "2026-10-24T12:47:58+00:00"}]
---

# open62541: integer overflow in OPC UA client datatype parsing enables heap overflow

open62541 1.5.0 before 1.5.7 wraps a 16-bit memory size field when it parses large custom structure definitions from a server. A malicious OPC UA server can use this to overflow the heap in a connecting client, crashing it or possibly running code.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the open62541 version the client application is built or linked against, e.g. `1.5.0` through `1.5.6` are affected
- Look for calls to `UA_Client_getRemoteDataTypes()` in the client code, since that is the path that reaches the flaw

## Fix

- Upgrade open62541 to `1.5.7` or later
- Until upgraded, avoid calling `UA_Client_getRemoteDataTypes()` against servers you do not fully trust

## Timeline

- 2026-10-24T12:47:58+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-116014

## From the sources

open62541 1.5.0 before 1.5.7 contains an integer overflow in UA_DataType_fromStructureDescription() that wraps the 16-bit memSize field for large custom structure definitions. A malicious OPC UA server can supply DataType definitions via UA_Client_getRemoteDataTypes(), causing decodeBinaryStructure() to overflow the heap, crashing clients or enabling code execution.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_