Cisco IOS tunneled denial of service

ciscoios-tunneled-dos (78883) The risk level is classified as MediumMedium Risk


Cisco IOS is vulnerable to a denial of service, caused by an error when handling certain tunneled packets. By sending tunneled IP packets, a remote attacker could exploit this vulnerability to cause the device to be unable to process traffic on the affected interface.


Base Score: 7.8
  Access Vector: Network
  Access Complexity: Low
  Authentication: None
  Confidentiality Impact: None
  Integrity Impact: None
  Availability Impact: Complete
Temporal Score: 5.8
  Exploitability: Unproven
  Remediation Level: Official-Fix
  Report Confidence: Confirmed


Denial of Service


Refer to cisco-sa-20120926-c10k-tunnels for patch, upgrade or suggested workaround information. See References.


  • cisco-sa-20120926-c10k-tunnels: Cisco IOS Software Tunneled Traffic Queue Wedge Vulnerability .
  • BID-55696: Cisco IOS Queue Wedge CVE-2012-4620 Denial of Service Vulnerability
  • CVE-2012-4620: Cisco IOS 12.2 and 15.0 through 15.2 on Cisco 10000 series routers, when a tunnel interface exists, allows remote attackers to cause a denial of service (interface queue wedge) via tunneled (1) GRE/IP, (2) IPIP, or (3) IPv6 in IPv4 packets, aka Bug ID CSCts66808.
  • OSVDB ID: 85811: Cisco IOS Malformed Tunneled Packet Handling Remote DoS
  • SA50771: Cisco IOS Cisco 10000 Series Routers Tunneled Packets Handling Denial of Service Vulnerability

Platforms Affected:

  • Cisco IOS 12.4
  • Cisco IOS 15.0
  • Cisco IOS 15.1
  • Cisco IOS 15.2


Sep 26, 2012

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