Client crash via unchecked response result count
Published Aug 5, 2026 · Updated Aug 5, 2026
Out-of-bounds read in Systerel S2OPC 1.7.3 allows man-in-the-middle attackers to crash client wrapper applications via a malformed response. LockedStaMac_ProcessMsg_DeleteMonitoredItemsResponse trusts the response NoOfResults value as its loop bound, then indexes the shorter saved MonitoredItemIds request array without comparing their counts. Remote attackers controlling an OPC UA server, or man-in-the-middle attackers able to alter an established session, can trigger a one-past-end heap read and abort the client process.
Summary
What happened
Out-of-bounds read in Systerel S2OPC 1.7.3 allows man-in-the-middle attackers to crash client wrapper applications via a malformed response. LockedStaMac_ProcessMsg_DeleteMonitoredItemsResponse trusts the response NoOfResults value as its loop bound, then indexes the shorter saved MonitoredItemIds request array without comparing their counts. Remote attackers controlling an OPC UA server, or man-in-the-middle attackers able to alter an established session, can trigger a one-past-end heap read and abort the client process.
The record
- CVE
- CVE-2026-67866
- Published
- Aug 5, 2026
- Updated
- Aug 5, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-121, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 5, 2026CVE publishedPublication date reported by the CVE source.
- Aug 5, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
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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.
Weakness, pattern, technique
Public exploit references
- DeleteMonitoredItemsResponse result-count PoCproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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