CVE-2026-18785Public exploitNetwork attack vector

Client crash via unbounded subtype recursion

Published Aug 4, 2026 · Updated Aug 4, 2026

Stack exhaustion in open62541 allows remote attackers controlling an OPC UA server to crash clients during custom datatype discovery. The browseDataTypesRecursive helper recursively follows each fresh HasSubtype node without a depth, node, or request limit. Exploitation requires a client at commit ca356b088ada7dee824d1b4acd07c1ff07ce242b to connect to the malicious server and call UA_Client_getRemoteDataTypes, terminating that client process.

CVSS severity5.3
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack exhaustion in open62541 allows remote attackers controlling an OPC UA server to crash clients during custom datatype discovery. The browseDataTypesRecursive helper recursively follows each fresh HasSubtype node without a depth, node, or request limit. Exploitation requires a client at commit ca356b088ada7dee824d1b4acd07c1ff07ce242b to connect to the malicious server and call UA_Client_getRemoteDataTypes, terminating that client process.

The record

CVE
CVE-2026-18785
Published
Aug 4, 2026
Updated
Aug 4, 2026
Vendor
o6 Automation GmbH
Product
open62541
Classifications
CWE-119, CWE-416, T1499
Attack vector
network
Privileges
Unavailable

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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=ca356b088ada7dee824d1b4acd07c1ff07ce242b

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

o6 Automation GmbH · open62541version=ca356b088ada7dee824d1b4acd07c1ff07ce242b

Published CVSS scores

4.3VulDBAV:L/AC:L/Au:S/C:P/I:P/A:P
5.3VulDBCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
1.9VulDBCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P

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
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
CWE-416Use After Free
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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