CVE-2020-13573Network attack vector

Unauthenticated crash via unchecked Address Item Length

Published Jan 7, 2021 · Updated Aug 4, 2024

Out-of-bounds read in Rockwell Automation RSLinx Classic 4.50.00 and earlier allows remote attackers to crash its Ethernet/IP server. After Register Session, Send Unit Data accepts an Address Item Length without checking it against the received data, advances a pointer outside mapped memory, and dereferences it. No authentication or user interaction is required, and the application remains unresponsive until manually restarted.

CVSS severity7.5
High
EPSS probability3.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in Rockwell Automation RSLinx Classic 4.50.00 and earlier allows remote attackers to crash its Ethernet/IP server. After Register Session, Send Unit Data accepts an Address Item Length without checking it against the received data, advances a pointer outside mapped memory, and dereferences it. No authentication or user interaction is required, and the application remains unresponsive until manually restarted.

The record

CVE
CVE-2020-13573
Published
Jan 7, 2021
Updated
Aug 4, 2024
Vendor
Rockwell Automation
Product
RSLinx Classic
Classifications
CWE-125, CWE-823, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 7, 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=Rockwell Automation RSLinx Classic 2.57.00.14 CPR 9 SR 3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Rockwell Automation · RSLinx Classicversion=Rockwell Automation RSLinx Classic 2.57.00.14 CPR 9 SR 3

Published CVSS scores

7.5Cisco TalosCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5NVDCVSS:3.1/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-125Out-of-bounds Read
CWE-823Use of Out-of-range Pointer Offset
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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