Last Modified: Aug 19, 2026
Affected Product(s):
BIG-IP LTM, TMOS
Known Affected Versions:
11.5.1, 11.5.1 hf1, 11.5.1 hf2, 11.5.1 hf3, 11.5.1 hf4, 11.5.1 hf5, 11.5.1 hf6, 11.5.1 hf7, 11.5.1 hf8, 11.5.1 hf9, 11.5.1 hf10, 11.5.1 hf11, 11.5.2, 11.5.2 hf1, 11.5.3, 11.5.3 hf1, 11.5.3 hf2, 11.5.4, 11.5.4 hf1, 11.5.4 hf2, 11.5.4 hf3, 11.5.4 hf4, 11.5.5, 11.5.6, 11.5.7, 11.5.8, 11.5.9, 11.5.10, 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:
12.0.0
Opened: Nov 12, 2014 Severity: 3-Major Related Article:
K17400
When a TLS client connects to a BIG-IP TLS server requesting TLS1.3, the handshake will fail. A message will be logged in the Local Traffic Manager (LTM) log about a handshake failure. The estimated deployment of clients supporting TLS1.3 is 2016.
Lower performance is the most likely outcome. The hanshake requesting TLS1.3 will fail, after which a client will reconnect with a TLS 1.2 hanhdshake and succeed. The worst case scenario is inability to establish a connection for clients that only implement standard TLS version negotiation mechanism. The estimated deployment of clients supporting TLS1.3 is 2016.
A TLS client handshake with the protocol version set to TLS1.3 in the ClientHello.
This issue has no workaround at this time.
TLS server code can now handle ClientHello.protocol_version that is higher than TLS1.2, according to the TLS1.2 specification.