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Cisco Bug: CSCvr99034 - ISR 4K router crash during updating the OpenDNS bypass whitelist

Last Modified

May 26, 2020

Products (14)

  • Cisco IOS
  • Cisco ASR 1000 Series IOS XE SD-WAN
  • Cisco 4221 Integrated Services Router
  • Cisco ASR 1002-X Router
  • Cisco 4321 Integrated Services Router
  • Cisco 4331 Integrated Services Router
  • Cisco ASR 1001-X Router
  • Cisco 4351 Integrated Services Router
  • Cisco ASR 1002-HX Router
  • Cisco ISR 1000 Series IOS XE SD-WAN
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Known Affected Releases

16.9.4

Description (partial)

Symptom:
Using the ISR router as an OpenDNS pass-through server.

The .* compilation takes much time in regex library resulting in CPU hogging leading to a crash.

Example:
parameter-map type regex LOCAL_DOMAINS
pattern .*webex.*
pattern .*cisco.*
pattern .*google.*
pattern .*facebook.*
pattern .*amazon.*
pattern .*cnn.*
pattern .*mycompany.*
pattern .*yourcompany.*

Conditions:
Router cannot handle more than 7 entries with greedy .* matching at the beginning and end of the regular expression. For example: .*webex.* It is not recommended to use this kind of patterns.
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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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