Bug ID 1623669: False “Illegal dynamic parameter value” violations when extracting parameters from links (HREF)

Last Modified: Jan 13, 2026

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

Known Affected Versions:
17.1.0, 17.1.0.1, 17.1.0.2, 17.1.0.3, 17.1.1, 17.1.1.1, 17.1.1.2, 17.1.1.3, 17.1.1.4, 17.1.2, 17.1.2.1, 17.1.2.2, 17.1.3

Opened: Aug 05, 2024

Severity: 3-Major

Symptoms

Requests may be blocked with the violation “Illegal dynamic parameter value” even though the parameter values were correctly extracted from application responses using “Search in Links” and should be treated as valid.

Impact

Legitimate application traffic may be blocked because values extracted from links are not recognized as valid dynamic parameter values.

Conditions

- A parameter is configured with Dynamic content value - “Check – Search in Links” is enabled for the parameter - The parameter value is extracted from response links (HREF) - The extracted value is later used in a client request while the policy is enforced

Workaround

None

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips