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Cisco Bug: CSCuq31566 - telnetd crash when receiving malformed telnet packet

Last Modified

Aug 07, 2018

Products (7)

  • Cisco Network Convergence System 6000 Series Routers
  • Cisco IOS XR Software
  • Cisco ASR 9922 Router
  • Cisco ASR 9010 Router
  • Cisco ASR 9006 Router
  • Cisco ASR 9001 Router
  • Cisco ASR 9912 Router

Known Affected Releases


Description (partial)

A vulnerability in telnetd process of Cisco IOS XR could allow an unauthenticated, remote attacker to cause a reload of the affected service.

The vulnerability is due to improper processing of malformed telnet packet directed to a device configured to process such packets to itself. An attacker could exploit 
this vulnerability by sending a malformed telnet packet to a device that is configured to accept telnet connections to itself and process them for remote management. 
An exploit could allow the attacker to cause a reload of the affected service.
Cisco IOS XR device is configured to accept telnet connections for remote management.
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Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
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