# CVE-2026-116014: open62541 integer overflow in UA_DataType_fromStructureDescription()

Source: https://junglewise.ai/threats/cve-2026-116014-open62541-1-5-0-before-1-5-7-contains-an-integer-overflow-in-ua  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-24. Updated: 2026-10-24  
License: CC BY 4.0 with a link back

CVE-2026-116014 · Severity: high · CVSS 8.1 · Published 2026-10-24

open62541 is an OPC UA protocol library used by industrial control and automation systems to communicate across networks. A malicious OPC UA server can supply specially crafted data type definitions that trigger an integer overflow in the client library, causing the client application to crash or potentially allowing the attacker to execute arbitrary code on the client machine.

Vendors: [Open62541](https://junglewise.ai/threats/vendors/open62541).

## Quick answers

**Is CVE-2026-116014 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-116014 being exploited in the wild.

**How severe is CVE-2026-116014?** High severity, with a CVSS score of 8.1, published 24 October 2026.

**Which products and versions are affected?** Open62541 1.5.0 before 1.5.7.

**Is there a fix for CVE-2026-116014?** Yes: fixed in 1.5.7. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-116014 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-116014?** Check whether you run Open62541 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- Fixed in 1.5.7

## Technical details

An integer overflow in UA_DataType_fromStructureDescription() allows a 16-bit memSize field to wrap when processing custom structure definitions with cumulative member sizes exceeding 65535 bytes. When a malicious OPC UA server provides such definitions via UA_Client_getRemoteDataTypes(), the client's decodeBinaryStructure() function allocates a buffer using the wrapped (too-small) memSize but writes member data at true offsets, corrupting adjacent heap memory. This requires network connectivity to a malicious OPC UA server but no authentication or user interaction.

## Affected products

- open62541 open62541 1.5.0 before 1.5.7

## Timeline

- 2026-10-24: disclosed

## References

- [https://github.com/open62541/open62541/blob/v1.5.6/src/ua_types_definition.c](https://github.com/open62541/open62541/blob/v1.5.6/src/ua_types_definition.c)
- [https://github.com/open62541/open62541/commit/0cf4806768c493bc6ccffcd4419da24153b970ec](https://github.com/open62541/open62541/commit/0cf4806768c493bc6ccffcd4419da24153b970ec)