CVE-2026-9621: RSLinx Classic® - Multiple Vulnerabilities

Severity: critical (CVSS 9.2 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-01 · updated 2026-09-01
Weakness: CWE-190

Description

A denial-of-service security issue exists within RSLinx® Classic. The security issue stems from improper handling of a malformed packet. A crafted CIP packet can cause the RSLinx® Classic service to crash, requiring a restart of the service to recover

Affected products

Rockwell Automation RSLinx Classic®: through V4.50

References

https://www.rockwellautomation.com/en-us/trust-center/security-advisories/advisory.SD1794.html

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