Bug ID 531761: Web navigation flow may be reset when main page responds with non-HTML content

Last Modified: Jul 18, 2026

Affected Product(s):
BIG-IP ASM(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, 11.6.3.1, 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

Fixed In:
12.1.0, 12.0.0

Opened: Jul 03, 2015

Severity: 3-Major

Symptoms

In some web applications, the navigation flow may break (connection reset) if a main URL (login page, for example) is responding with a content that is not an HTML one, or if the response is dynamic, and occasionally not an HTML one.

Impact

Users may experience a connection reset while navigating through the website, usually after several minutes.

Conditions

Proactive Bot Defense is enabled on a DOS profile that is attached to a Virtual Server, and one of the main URLs of the web application (login page, home page, etc.) occasionally responds with a non-HTML content, blank content, or redirect response with no body.

Workaround

None

Fix Information

Connection resets are no longer experienced on normal web navigation of a site that is protected by the Proactive Bot Defense mechanism, and one of the main pages of the web application occasionally responds with a non-HTML content.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips