CVE-2020-27297Network attack vector

Remote code execution via item-count integer overflow

Published Jan 26, 2021 · Updated Aug 4, 2024

Heap-based buffer overflow in Honeywell Technologies Matrikon OPC UA Tunneller before 6.3.0.8233 allows remote attackers to execute code. Its proprietary-protocol decoder multiplies an untrusted 32-bit item_count by each structure's size without validation, so integer wraparound makes malloc reserve a buffer smaller than the subsequent item loop fills. The server-side tunneller accepts the crafted TCP packet without authentication on 32-bit systems, allowing controlled heap corruption and process takeover.

CVSS severity9.8
Critical
EPSS probability2.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in Honeywell Technologies Matrikon OPC UA Tunneller before 6.3.0.8233 allows remote attackers to execute code. Its proprietary-protocol decoder multiplies an untrusted 32-bit item_count by each structure's size without validation, so integer wraparound makes malloc reserve a buffer smaller than the subsequent item loop fills. The server-side tunneller accepts the crafted TCP packet without authentication on 32-bit systems, allowing controlled heap corruption and process takeover.

The record

CVE
CVE-2020-27297
Published
Jan 26, 2021
Updated
Aug 4, 2024
Vendor
Honeywell Technologies
Product
Matrikon OPC UA Tunneller
Classifications
CWE-787, CWE-122, T1210
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

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/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-787Out-of-bounds Write
CWE-122Heap-based Buffer Overflow
T1210Exploitation of Remote Services

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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