Cisco IOS, XR, and XE Software Buffer Overflow Vulnerability
What it is
There is a buffer overflow vulnerability in the Link Layer Discovery Protocol (LLDP) subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software which could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition or execute arbitrary code.
Who's affected
Affects anyone with Cisco networking or security appliances on their network — typically a firewall, switch, or remote-access VPN. That device controls traffic to and from every workstation; exploitation can mean an attacker pivots inside the network without touching any user device.
What to do
Apply updates per vendor instructions.
CISA action deadline: March 17, 2022. Federal agencies must complete the required action by this date. For private SMBs the deadline is advisory — but treat it as a strong recommendation, especially if you handle regulated data (HIPAA, GLBA, ABA model rules).
If you don't have someone in-house to verify the patch deployed across every endpoint — or you're not sure whether you're affected — that's exactly the kind of triage we do. Book a free 20-minute triage call.
Severity
CVSS base score: 8.8 — HIGH
Weakness classification: CWE-119
Source
Pulled daily from the public cisagov/kev-data mirror (CC0). View the original entry on cisa.gov. CISA KEV is US-Government public-domain data; we add the SMB-vertical framing and the coping action above.