CVE-2020-6088Network attack vector

Communications loss via oversized ENIP segment length

Published Feb 4, 2021 · Updated Aug 4, 2024

Buffer overflow in Rockwell Automation 1794-AENT FLEX I/O Adapter 4.003 and earlier allows remote attackers to interrupt communications. The ENIP SendRRData Request Path parser treats a reserved Network Segment subtype's following byte as a word length without confirming that the declared segment fits the remaining packet. An unauthenticated attacker whose EtherNet/IP packets reach the adapter can force a fault state that remains unresponsive until a physical power cycle.

CVSS severity7.5
High
EPSS probability3.45%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in Rockwell Automation 1794-AENT FLEX I/O Adapter 4.003 and earlier allows remote attackers to interrupt communications. The ENIP SendRRData Request Path parser treats a reserved Network Segment subtype's following byte as a word length without confirming that the declared segment fits the remaining packet. An unauthenticated attacker whose EtherNet/IP packets reach the adapter can force a fault state that remains unresponsive until a physical power cycle.

The record

CVE
CVE-2020-6088
Published
Feb 4, 2021
Updated
Aug 4, 2024
Vendor
Rockwell Automation
Product
1794-AENT FLEX I/O EtherNet/IP Adapter Module
Classifications
CWE-120, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 4, 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=Allen-Bradley Flex IO 1794-AENT/B 4.003

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Rockwell Automation · 1794-AENT FLEX I/O EtherNet/IP Adapter Moduleversion=Allen-Bradley Flex IO 1794-AENT/B 4.003

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
7.5Cisco TalosCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Application or System Exploitation

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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