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Research > Zero-Day Tracker > 20070912

Cisco IOS Regular Expressions Denial of Service

Date Disclosed:

Date Patched:


Affected Software:
Cisco IOS 12.0, 12.1, 12.2, 12.3, and 12.4

A vulnerability within Cisco IOS could allow remote unauthenticated attackers to send specially crafted commands to an affected device and cause a denial of service condition, due to a bug in how regular expressions are parsed.


Code Execution:

Denial of Service
Exploitation of this vulnerability is possible by sending certain specially crafted commands to affected devices. When processing the commands, the devices will stop responding, resulting in a denial of service condition.


BeyondTrust's Retina® Network Security Scanner scans devices to detect for this vulnerability.

  • 11841 - Cisco IOS Regular Expressions Denial of Service – SNMP
  • 11842 - Cisco IOS Regular Expressions Denial of Service - Credentialed


9.12.2007 - Vendor Advisory Released
9.11.2012 - Vendor Patch Released

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