CVE-2011-4499: Cisco Linksys WRT54G Router Firmware

High severity, CVSS 7.5. EPSS: 1.3% chance of exploitation in the next 30 days.

The UPnP IGD implementation in the Broadcom UPnP stack on the Cisco Linksys WRT54G with firmware before 4.30.5, WRT54GS v1 through v3 with firmware before 4.71.1, and WRT54GS v4 with firmware before 1.06.1 allows remote attackers to establish arbitrary port mappings by sending a UPnP AddPortMapping action in a SOAP request to the WAN interface, related to an "external forwarding" vulnerability.

Affected products

• Cisco Linksys WRT54G Router Firmware: up to and including 4.20.8; version 3.03.9 only; version 4.20.7 only
• Cisco Linksys WRT54GS Router Firmware: up to and including 4.70.6; version 2.09.1 only; up to and including 1.06
• Linksys WRT54G
• Linksys WRT54GS

Published 2011-11-22. Last modified 2026-06-16.