CVE-2026-67862Public exploitNetwork attack vector

Client crash via unchecked NodeClass response type

Published Aug 4, 2026 · Updated Aug 4, 2026

Heap buffer overflow in open62541 1.5.5 allows remote attackers controlling an OPC UA server to crash a connected client process. The __Client_readAttribute function copies sizeof(UA_NodeClass) bytes from a NodeClass response without verifying that the decoded Variant is scalar and has the NodeClass type. Exploitation requires the client to connect to a malicious or compromised server and call the high-level NodeClass attribute reader; the demonstrated consequence is a client-process crash.

CVSS severity7.5
High
EPSS probability0.33%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in open62541 1.5.5 allows remote attackers controlling an OPC UA server to crash a connected client process. The __Client_readAttribute function copies sizeof(UA_NodeClass) bytes from a NodeClass response without verifying that the decoded Variant is scalar and has the NodeClass type. Exploitation requires the client to connect to a malicious or compromised server and call the high-level NodeClass attribute reader; the demonstrated consequence is a client-process crash.

The record

CVE
CVE-2026-67862
Published
Aug 4, 2026
Updated
Aug 4, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-400, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-400Uncontrolled Resource Consumption
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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