What is CVE-2019-6553?

CVE-2019-6553 is a critical-severity vulnerability in Rockwell Automation Rslinx Classic, classified under Stack-based Buffer Overflow. CVSS score: 9.8/10. Published 2019-04-04.

How severe is CVE-2019-6553?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Buffer overflow in Rockwell Automation Rslinx Classic

CVE-2019-6553

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.

Vulnerability class: Buffer Overflow

Published 2019-04-04 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.663 (99.3th percentile), scored 2026-10-29.

High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 99.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.661 · newest: 0.663 · change: +0.002

Affected products

Rockwell Automation Rslinx Classic — versions 4.10.00 and prior
Rockwellautomation Rslinx

Weakness classification (CWE)

References

ics-cert.us-cert.gov/advisories/ICSA-19-064-01 (US Government Resource, Third Party Advisory)

Frequently asked questions

What is CVE-2019-6553?: CVE-2019-6553 is a critical-severity vulnerability in Rockwell Automation Rslinx Classic, classified under Stack-based Buffer Overflow. CVSS score: 9.8/10. Published 2019-04-04.
How severe is CVE-2019-6553?: Critical severity. CVSS v3 base score is 9.8 out of 10.