The issue appears to be that EAP 6.4.21 does not parse the field-name in accordance to RFC7230[1] as it returns a 200 instead of a 400.
This issue has been addressed in the following products: Red Hat JBoss Enterprise Application Platform Via RHSA-2020:3464 https://access.redhat.com/errata/RHSA-2020:3464
This issue has been addressed in the following products: Red Hat JBoss Enterprise Application Platform 7.3 for RHEL 6 Via RHSA-2020:3461 https://access.redhat.com/errata/RHSA-2020:3461
This issue has been addressed in the following products: Red Hat JBoss Enterprise Application Platform 7.3 for RHEL 7 Via RHSA-2020:3462 https://access.redhat.com/errata/RHSA-2020:3462
This issue has been addressed in the following products: Red Hat JBoss Enterprise Application Platform 7.3 for RHEL 8 Via RHSA-2020:3463 https://access.redhat.com/errata/RHSA-2020:3463
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s): https://access.redhat.com/security/cve/cve-2020-1710
This issue has been addressed in the following products: Red Hat Single Sign-On 7.4.2 Via RHSA-2020:3501 https://access.redhat.com/errata/RHSA-2020:3501
Mitigation: There is currently no known mitigation for this issue.
This issue has been addressed in the following products: Red Hat Openshift Application Runtimes Via RHSA-2020:3539 https://access.redhat.com/errata/RHSA-2020:3539
This issue has been addressed in the following products: Red Hat JBoss Enterprise Application Platform 7.2 for RHEL 6 Via RHSA-2020:3637 https://access.redhat.com/errata/RHSA-2020:3637
This issue has been addressed in the following products: Red Hat JBoss Enterprise Application Platform 7.2 for RHEL 8 Via RHSA-2020:3639 https://access.redhat.com/errata/RHSA-2020:3639
This issue has been addressed in the following products: Red Hat JBoss Enterprise Application Platform 7.2 for RHEL 7 Via RHSA-2020:3638 https://access.redhat.com/errata/RHSA-2020:3638
This issue has been addressed in the following products: Red Hat JBoss Enterprise Application Platform Via RHSA-2020:3642 https://access.redhat.com/errata/RHSA-2020:3642
This issue has been addressed in the following products: Red Hat Data Grid 7.3.7 Via RHSA-2020:3779 https://access.redhat.com/errata/RHSA-2020:3779