Linksys WRT54G UPnP AddPortMapping security bypass

linksys-upnp-security-bypass (26707) The risk level is classified as LowLow Risk


The Linksys WRT54G Wireless-G Broadband Router could allow a remote attacker to bypass security restrictions and forward arbitrary traffic, caused by a vulnerability in the Universal Plug and Play (UPnP) service. An attacker could exploit this vulnerability by sending a specially-crafted AddPortMapping request with an invalid 'InternalClient' parameter.


Bypass Security


Upgrade to the latest firmware version (1.00.9 or later), available from the Linksys Web site. See References.


  • LInksys Web site: Downloads/Firmware.
  • Securityview Web site: How does the UPnP flaw works.
  • CVE-2006-2559: Linksys WRT54G Wireless-G Broadband Router allows remote attackers to bypass access restrictions and conduct unauthorized operations via a UPnP request with a modified InternalClient parameter, which is not validated, as demonstrated by using AddPortMapping to forward arbitrary traffic.
  • OSVDB ID: 25894: Multiple Router UPnP Crafted InternalClient Parameter Access Restriction Bypass
  • OSVDB ID: 27807: Cisco Linksys WRT54G Security.tri Unauthenticated Configuration Modification
  • OSVDB ID: 27808: Cisco Linksys WRT54G Web Admin Console CSRF
  • SA20161: Linksys WRT54G UPnP Port Mapping Vulnerability
  • SECTRACK ID: 1016134: Linksys WRT54GS UPnP Bug Lets Remote Internal Users Cause Packets to Be Forwarded to External Systems

Platforms Affected:

  • Linksys WRT54G v5


May 22, 2006

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