Last Modified: Aug 19, 2026
Affected Product(s):
BIG-IP All
Known Affected Versions:
11.5.4, 11.5.4 hf1, 11.5.4 hf2, 11.5.4 hf3, 11.5.4 hf4, 11.5.5, 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, 12.1.2, 12.1.2 hf1, 12.1.2 hf2, 12.1.3, 12.1.3.1, 12.1.3.2, 12.1.3.3, 12.1.3.4, 12.1.3.5, 12.1.3.6, 12.1.3.7, 12.1.4, 12.1.4.1, 12.1.5, 12.1.5.1, 12.1.5.2, 12.1.5.3, 12.1.6
Fixed In:
13.0.0, 11.6.3.2, 11.5.6
Opened: Oct 14, 2016 Severity: 2-Critical
BIG-IP entry to SYN cookie mode may not occur even though traffic pattern would dictate that it should.
BIG-IP does not enter SYN cookie mode at the expected time.
Verified accept enabled on a Virtual IP. Large volume of traffic being processed by BIG-IP.
Disable verified accept on all VIP TCP profiles.
BIG-IP correctly enters SYN cookie mode when traffic pattern dictates that it should.