CVE-2026-63035Network attack vector

Code execution via stale subscription backpointers

Published Jul 30, 2026 · Updated Jul 30, 2026

Heap use-after-free in open62541's TransferSubscriptions service allows remote authenticated users to execute code or crash the server. Operation_TransferSubscription copies a subscription without migrating its samplingMonitoredItems list, leaving backpointers into the freed original structure. An authenticated OPC UA session must transfer a subscription containing publish-sampled monitored items; later sampling removal writes through a stale pointer and corrupts heap memory.

CVSS severity7.2
High
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap use-after-free in open62541's TransferSubscriptions service allows remote authenticated users to execute code or crash the server. Operation_TransferSubscription copies a subscription without migrating its samplingMonitoredItems list, leaving backpointers into the freed original structure. An authenticated OPC UA session must transfer a subscription containing publish-sampled monitored items; later sampling removal writes through a stale pointer and corrupts heap memory.

The record

CVE
CVE-2026-63035
Published
Jul 30, 2026
Updated
Jul 30, 2026
Vendor
o6 Automation GmbH
Product
open62541
Classifications
CWE-416, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 30, 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=1.3.0 <=1.3.17
  2. Affected versionversion=1.4.0 <=1.4.16
  3. Affected versionversion=1.5.0 <=1.5.4
  4. Affected versionversion=master

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

o6 Automation GmbH · open62541version=1.3.0 <=1.3.17; version=1.4.0 <=1.4.16; version=1.5.0 <=1.5.4; version=master

Published CVSS scores

7.2ICS-CERTCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
8.1ICS-CERTCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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