Last Modified: May 23, 2026
Affected Product(s):
BIG-IP LTM
Known Affected Versions:
17.1.3, 17.1.3.1, 17.1.3.2, 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, 21.0.0, 21.0.0.1
Opened: Dec 30, 2025 Severity: 3-Major
SSL handshakes fail on the client due to an Illegal Parameter alert.
SSL handshake fails and the connection terminates
ClientSSL that mixes both FFDHE and Non-FFDHE groups and has session tickets enabled. The client tries to resume an SSL session with a Non-FFDHE key share that used FFDHE previously.
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