CVE-2020-27274Network attack vector

Service interruption via unchecked malloc return

Published Jan 26, 2021 · Updated Aug 4, 2024

Denial of service in Honeywell Matrikon OPC UA Tunneller before 6.3.0.8233 allows remote attackers to close a message thread. Parsing functions fail to check whether malloc returns a null pointer before using the allocation, forcing the thread handling the crafted message to close. No authentication or user interaction is required, and the documented consequence is interruption of message handling rather than process-wide code execution.

CVSS severity7.5
High
EPSS probability1.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Honeywell Matrikon OPC UA Tunneller before 6.3.0.8233 allows remote attackers to close a message thread. Parsing functions fail to check whether malloc returns a null pointer before using the allocation, forcing the thread handling the crafted message to close. No authentication or user interaction is required, and the documented consequence is interruption of message handling rather than process-wide code execution.

The record

CVE
CVE-2020-27274
Published
Jan 26, 2021
Updated
Aug 4, 2024
Vendor
Honeywell Technologies
Product
Matrikon OPC UA Tunneller
Classifications
CWE-754, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 26, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record 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=All versions prior to 6.3.0.8233

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Honeywell Technologies · Matrikon OPC UA Tunnellerversion=All versions prior to 6.3.0.8233

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A: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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-754Improper Check for Unusual or Exceptional Conditions
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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