Client crash via unchecked NamespaceArray length
Published Aug 4, 2026 · Updated Aug 4, 2026
Out-of-bounds read in open62541 1.5.5 allows remote attackers to crash a connecting client via a crafted OPC UA NamespaceArray. responseReadNamespacesArray() accepts a ReadResponse without verifying resultsSize or the NamespaceArray length, then dereferences results[0] and ns[1]. A client must connect to an attacker-controlled OPC UA server that returns an empty or undersized array; the invalid read can terminate the client process.
Summary
What happened
Out-of-bounds read in open62541 1.5.5 allows remote attackers to crash a connecting client via a crafted OPC UA NamespaceArray. responseReadNamespacesArray() accepts a ReadResponse without verifying resultsSize or the NamespaceArray length, then dereferences results[0] and ns[1]. A client must connect to an attacker-controlled OPC UA server that returns an empty or undersized array; the invalid read can terminate the client process.
The record
- CVE
- CVE-2026-67857
- Published
- Aug 4, 2026
- Updated
- Aug 4, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-125, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 4, 2026CVE publishedPublication date reported by the CVE source.
- Aug 4, 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
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.
Public exploit references
- NamespaceArray zero-results OPC UA server reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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