No exploitation reportedFix available

CVE-2019-6553

No exploitation reported by the sources we read.

Published2019-04-04
WeaknessCWE-121 · CWE-787

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A vulnerability was found in Rockwell Automation RSLinx Classic versions 4.10.00 and prior. An input validation issue in a .dll file of RSLinx Classic where the data in a Forward Open service request is passed to a fixed size buffer, allowing an attacker to exploit a stack-based buffer overflow condition.

Timeline

dates in UTC

2019-04-0419:29CVE publishedNVD
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2019-6553?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2019-6553?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Rockwellautomation rslinx

Branch	Affected	Fixed in	Source
4.10	≤ 4.10.00	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Vendor advisories

ICSA-19-064-01 CISA1 known affected
Rockwell Automation RSLinx Classic
RSLinx Classic: Versions 4.10.00 and prior

Full record on NVD

Fix

Vendor fix CISA ICSA-19-064-01 · 1 productRockwell Automation has released patches to address earlier versions of RSLinx Classic including v3.60, v3.70, v3.80, v3.81, v3.90, v4.00.01, v4.10. These patches can be found at Knowledgebase Article ID: 1084828
Vendor fix CISA ICSA-19-064-01 · 1 productRockwell Automation has also stated that users may disable Port 44818 in RSLinx Classic if it is not utilized during system operation. To disable Port 44818, go to Options in RSLinx Classic. Then in the General tab of the Options pop-up, uncheck the option “Accept UDP Messages on Ethernet Port”.
Vendor fix CISA ICSA-19-064-01 · 1 productPort 44818 is needed only when a user wants to utilize unsolicited messages. To check if you are using unsolicited messages, go to the “DDE/OPC” dropdown in RSLinx Classic. Select Topic Configuration and then go to the Data Collection tab in the Topic Configuration pop-up. If the “Unsolicited Messa…
Vendor fix CISA ICSA-19-064-01 · 1 productNOTE: In RSLinx Classic 4.10 or later, “Accept UDP Messages on Ethernet Port” checkbox is unchecked by default.
Mitigation from the vendor CISA ICSA-19-064-01 · 1 productFor more information please see the Rockwell Automation security advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
CNAweakness (CWE)CWE-121read 2026-10-23
NVDweakness (CWE)CWE-787read 2026-10-23
FIRST EPSSEPSS score66.3 %read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2019-04-04
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2019-6553?

Is CVE-2019-6553 actively exploited?

Active exploitation of CVE-2019-6553 has not been confirmed. Its EPSS score was 66.3% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2019-6553?

CVE-2019-6553 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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