Is CVE-2026-67859 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-67859 being exploited in the wild.

How severe is CVE-2026-67859?

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

Is there a fix for CVE-2026-67859?

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-2026-67859 attacked?

It is attacked over the network.

Am I affected by CVE-2026-67859?

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-2026-67859: open62541 buffer overflow in Discovery/LDS handling

CVE-2026-67859 · Severity: high · CVSS 7.5 · Published 2026-08-04

open62541 is an open-source OPC UA server implementation used in industrial automation and IoT systems for device communication and discovery. A buffer overflow vulnerability in the Local Discovery Server (LDS) component allows a remote attacker to trigger a denial of service by sending specially crafted discovery packets, potentially causing the server to crash and disrupting critical industrial operations.

Quick answers

Is CVE-2026-67859 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-67859 being exploited in the wild.
How severe is CVE-2026-67859?: High severity, with a CVSS score of 7.5, published 4 August 2026.
Which products and versions are affected?: open62541 open62541 v1.5.5.
Is there a fix for CVE-2026-67859?: 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-2026-67859 attacked?: It is attacked over the network.
Am I affected by CVE-2026-67859?: 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

A buffer overflow vulnerability exists in open62541 v1.5.5 within the Discovery/LDS (Local Discovery Server) handling mechanism. The vulnerability is triggered via malformed discovery protocol messages that exceed buffer boundaries in the LDS processing logic. An attacker on the network can send crafted packets to the discovery service without authentication to trigger the overflow, causing abnormal process termination. While currently classified as a denial-of-service vector, buffer overflows can potentially be exploited for code execution depending on memory layout and protections. Patches are expected to be available in subsequent releases.

Affected products

open62541 open62541 v1.5.5

Timeline

2026-08-04: disclosed

References

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