Bug ID 1856529: DTLS1.2 handshakes are causing TMM crash with mTLS connection

Last Modified: Oct 19, 2025

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

Known Affected Versions:
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, 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

Fixed In:
17.5.1, 17.1.3, 16.1.6.1

Opened: Mar 17, 2025

Severity: 3-Major

Symptoms

A backend server configured with the mTLS connection type, the selected protocol is DTLS1.2 and the ssl-sign-hash value is "Any" then a TMM crash occurs during the handshake.

Impact

Traffic disrupted while tmm restarts.

Conditions

ServerSSL profile configured with, - key and certificate - the ssl-sign-hash value is "Any" A backend server is configured with DTLS1.2 protocol and client authentication is enabled.

Workaround

In server SSL profile, select the ssl-sign-hash to SHA-256.

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips