Bug ID 1053561: TLS 1.3 Handshake fails when 0RTT enabled on the client-side SSL and iRule is specified

Last Modified: Jan 26, 2026

Affected Product(s):
BIG-IP LTM(all modules)

Known Affected Versions:
15.1.3, 15.1.3.1, 15.1.4, 15.1.4.1, 15.1.5, 15.1.5.1, 15.1.6, 15.1.6.1, 15.1.7, 15.1.8, 15.1.8.1, 15.1.8.2, 15.1.9, 15.1.9.1, 15.1.10, 15.1.10.2, 15.1.10.3, 15.1.10.4, 15.1.10.5, 15.1.10.6, 15.1.10.7, 15.1.10.8, 16.1.0, 16.1.1, 16.1.2, 16.1.2.1, 16.1.2.2, 16.1.3, 16.1.3.1, 16.1.3.2, 16.1.3.3, 16.1.3.4, 16.1.3.5, 16.1.4, 16.1.4.1, 16.1.4.2, 16.1.4.3, 16.1.5, 16.1.5.1, 16.1.5.2, 16.1.6, 16.1.6.1

Opened: Oct 08, 2021

Severity: 2-Critical

Symptoms

On small virtual machines (e.g. 2 cores, 4GB RAM) when OpenSSL-1.1.1 client connects to a BIG-IP device running TLS 1.3, and containing an iRule, the handshake fails.

Impact

The handshake is terminated.

Conditions

1. Small virtual machine (e.g. one with 2 cores and 4GB RAM). 2. TLS 1.3 is enabled on the BIG-IP device. 3. An iRule is specified for client-side SSL.

Workaround

Disable TLS 1.3 on the BIG-IP device only if an alternative protocol is available.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips