CVE-2026-9621
CriticalCVSS 9.2Summary
A denial-of-service issue exists in RSLinx Classic due to improper handling of a malformed packet. A crafted CIP packet can crash the service, requiring restart.
Risk Assessment
An attacker could cause service unavailability, disrupting communication with industrial devices and affecting operations.
Recommendation
Update RSLinx Classic to the latest version and implement network filters to block malformed CIP packets.
Other vulnerabilities in RSLinx Classic
See all- CVE-2026-9625High
Denial-of-service vulnerability in RSLinx Classic. A crafted CIP packet with an oversized embedded message request can crash the RSLinx Classic service, requiring a restart to recover.
- CVE-2026-9624High
Denial-of-service vulnerability in RSLinx Classic. A crafted CIP packet can crash the RSLinx Classic service due to insufficient data length validation, requiring a restart to recover.
- CVE-2026-9622High
A denial-of-service vulnerability exists in RSLinx Classic. A crafted CIP packet targeting the Forward Close service can crash the RSLinx Classic service, requiring a restart to recover.
Original NVD description (English source)
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