Bug ID 572144: WebSafe virtuals may deliver garbled responses

Last Modified: Aug 19, 2026

Affected Product(s):
BIG-IP FPS(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, 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, 11.6.3.1, 11.6.3.2, 11.6.3.3, 11.6.3.4, 11.6.4, 11.6.5, 11.6.5.1, 11.6.5.2, 11.6.5.3, 12.0.0, 12.0.0 hf1, 12.0.0 hf2, 12.0.0 hf3, 12.0.0 hf4

Fixed In:
12.1.0

Opened: Feb 05, 2016

Severity: 2-Critical

Symptoms

In some circumstances, responses which WebSafe is not interested in may not be forwarded correctly, resulting in empty and/or garbled responses on the same connection.

Impact

The garbled responses may break the web application.

Conditions

Virtual with WebSafe configured, typically occurs with ASM also present on the virtual.

Workaround

No workaround short of not using the WebSafe feature.

Fix Information

Responses on WebSafe virtuals are now forwarded correctly without garbling.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips