Last Modified: Jul 28, 2026
Affected Product(s):
BIG-IP LTM
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, 17.1.3.1, 17.1.3.2, 17.1.3.4, 17.5.0, 17.5.1, 17.5.1.2, 17.5.1.3, 17.5.1.4, 17.5.1.5, 17.5.1.6, 17.5.1.8, 21.0.0, 21.0.0.1, 21.0.0.2, 21.0.0.3, 21.1.0, 21.1.0.1
Opened: Apr 14, 2026 Severity: 4-Minor
Under certain conditions, the BIG-IP might send an HTTP2 DATA frame followed by HEADERS frame. Since this is an incorrect sequence (per RFC9113 section 8.1) the receiving device might respond with PROTOCOL_ERROR hence terminating the stream.
Client sends PROTOCOL_ERROR in response to the incorrect BIG-IP HTTP2 sequence.
All of the below together: - HTTP::respond inside LB_FAILED - http2 profile - HTTP_REQUEST iRule event invoked Example iRule: when LB_FAILED { HTTP::respond 200 content "No available VS!\r\n" } when HTTP_REQUEST { }
Use HTTP::respond inside HTTP_REQUEST event instead. Use 'active_members' to check availability of pool. Example iRule: when HTTP_REQUEST { if { [active_members /Common/pool-01] < 1 } { HTTP::respond 200 content "No available VS!\r\n" } }
None