Bug ID 447515: CMP reply occasionally matches wrong connflow

Last Modified: Jul 18, 2026

Affected Product(s):
BIG-IP LTM(all modules)

Known Affected Versions:
11.5.1, 11.5.1 hf1, 11.5.1 hf2, 11.5.1 hf3, 11.5.1 hf4, 11.5.1 hf5, 11.5.1 hf6, 11.5.1 hf7, 11.5.1 hf8, 11.5.1 hf9, 11.5.1 hf10, 11.5.1 hf11, 11.5.2, 11.5.2 hf1, 11.5.3, 11.5.3 hf1, 11.5.3 hf2, 11.5.4, 11.5.4 hf1, 11.5.4 hf2, 11.5.4 hf3, 11.5.4 hf4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10

Fixed In:
11.6.0

Opened: Feb 06, 2014

Severity: 3-Major

Related Article: K15579

Symptoms

The system might crash and the CMP reply occasionally matches wrong connflow.

Impact

CMP msg may match a wrong connflow, even with the revised connflow cookie. In addition, TMM memory might grow.

Conditions

This intermittent issue occurs when TMM resumes a rule on a dead flow, which might occur at iRule resumption. This happens when an iRule is parked (e.g., for a table command), and then when the iRule is resumed, the related flow is already deleted from the conn table.

Workaround

As a possible workaround to help avoid the issue, if you are using a UDP profile, check the idle_timeout value. If it is set to a low number, such as 2, try raising this value to a larger value such as 30.

Fix Information

Resolved intermittent issue that could cause an eventual crash when an iRule was parked longer than the time-out which caused the flow to be deleted but then the iRule is resumed and becomes in a bad state due to the missing flow.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips