Is CVE-2026-67862 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-67862 being exploited in the wild.

How severe is CVE-2026-67862?

High severity, with a CVSS score of 7.5, published 4 August 2026.

Is there a fix for CVE-2026-67862?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-67862 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-67862?

Check whether anything you run is named in the advisory. 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.

CVE-2026-67862: open62541 heap-buffer-overflow in high-level attribute reading

CVE-2026-67862 · Severity: high · CVSS 7.5 · Published 2026-08-04

open62541 is a widely-used OPC UA protocol library that industrial systems, gateways, and diagnostic tools use to connect to manufacturing and infrastructure equipment. A malicious or compromised OPC UA server can trigger an out-of-bounds memory read in a client library function that retrieves node class attributes, causing the client process to crash and denying service to critical operational components.

Quick answers

Is CVE-2026-67862 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-67862 being exploited in the wild.
How severe is CVE-2026-67862?: High severity, with a CVSS score of 7.5, published 4 August 2026.
Which products and versions are affected?: open62541 open62541 1.5.5.
Is there a fix for CVE-2026-67862?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-67862 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-67862?: Check whether anything you run is named in the advisory. 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.

Technical details

The vulnerability is a heap-buffer-overflow in the __Client_readAttribute() function in src/client/ua_client_highlevel.c when reading the UA_ATTRIBUTEID_NODECLASS attribute. The vulnerable code performs a fixed 4-byte memcpy from res->value.data without validating that the server returned the expected NodeClass type; it skips the scalar-type validation checks applied to other attributes. A malicious server responding to a Read(NodeClass) request with a Boolean-typed Variant (memSize=1) instead triggers a 4-byte out-of-bounds heap read. The attack is reachable through standard OPC UA TCP negotiation and does not require special authentication. Impact is confirmed remote denial of service of client applications.

Affected products

open62541 open62541 1.5.5

Timeline

2026-08-04: disclosed

References

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