CVE-2026-67859Public exploitNetwork attack vector

Remote service crash via unbounded stack allocation

Published Aug 4, 2026 · Updated Aug 4, 2026

Stack exhaustion in open62541 1.5.5 allows remote attackers to crash discovery-enabled Local Discovery Server deployments. UA_Discovery_addRecord uses the unbounded attacker-controlled RegisterServer discoveryUrl.path length as the size of a variable-length stack allocation. Exploitation requires discovery and mDNS handling to be built and enabled; a single crafted request aborts the LDS process and interrupts OPC UA discovery.

CVSS severity7.5
High
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Stack exhaustion in open62541 1.5.5 allows remote attackers to crash discovery-enabled Local Discovery Server deployments. UA_Discovery_addRecord uses the unbounded attacker-controlled RegisterServer discoveryUrl.path length as the size of a variable-length stack allocation. Exploitation requires discovery and mDNS handling to be built and enabled; a single crafted request aborts the LDS process and interrupts OPC UA discovery.

The record

CVE
CVE-2026-67859
Published
Aug 4, 2026
Updated
Aug 4, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-120, 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

Compare your product and version with the public record. A matching version still requires validation against your environment.

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

7.5MITRECVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
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

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo