Asterisk – ConfBridge in Asterisk allow cause a denial of service

Advisory ID

Vulnerability Information



ConfBridge in Asterisk 11.x before 11.14.1 and Certified Asterisk 11.6 before 11.6-cert8 does not properly handle state changes, which allows remote attackers to cause a denial of service (channel hang and memory consumption) by causing transitions to be delayed, which triggers a state change from hung up to waiting for media.  For more information on the affected versions, CVE-2014-8414 was assigned for this bug.

Release Date


Technical Information


The ConfBridge application uses an internal bridging API to implement conference bridges. This internal API uses a state model for channels within the conference bridge and transitions between states as different things occur. Under load it is possible for some state transitions to be delayed causing the channel to transition from being hung up to waiting for media. As the channel has been hung up remotely no further media will arrive and the channel will stay within ConfBridge indefinitely.




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External Resources


Asterisk Project Security Advisory

Common Vulnerabilities and Exposures (CVE)