Bug ID 531982: SIP parser stuck after bad message

Last Modified: Mar 17, 2021

Bug Tracker

Affected Product:  See more info
BIG-IP LTM(all modules)

Known Affected Versions:
11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8, 11.6.1, 11.6.1 HF1, 11.6.1 HF2, 11.6.2, 11.6.2 HF1, 11.6.3,,,,, 11.6.4, 11.6.5,,,

Fixed In:

Opened: Jul 07, 2015
Severity: 3-Major


The SIP parser is designed to drop incorrectly formatted messages. In certain cases, the parser is unable to resume parsing once the incorrect message is dropped.


In certain setups where a connection is used for multiple messages or calls, a bad message could keep subsequent messages from being forwarded.


If multiple messages are received on the same connections, an incorrect messing on the connection may clog the parser and subsequent messages will not be parsed.



Fix Information

After a dropped message, parser is returned to a state where it is waiting for the next message.

Behavior Change