Last Modified: Jun 06, 2026
Affected Product(s):
BIG-IP APM
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, 17.5.1, 17.5.1.2, 17.5.1.3, 17.5.1.4, 17.5.1.5, 17.5.1.6
Opened: Dec 09, 2025 Severity: 3-Major
On BIG-IP APM systems, a crash of the Traffic Management Microkernel (TMM) may happen when a client device sends an unexpected extra trailing carriage return or line feed (CR/LF) during an iSession tunnel reconnection. This issue has been observed in a specific user scenario involving a certain client device. In this case, the Edge Client installation was a hybrid of multiple versions, which resulted in the transmission of these unexpected CR/LF characters following the iSession request.
-- Traffic is disrupted while the TMM restarts. -- Disruption of user sessions. -- The issue is highly specific to certain client configurations and is not expected to be widespread.
iSession tunnels in use. Client device sends an extra CR/LF after the iSession request, often due to a hybrid or corrupted Edge Client installation.
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