Bug ID 2261137: TMM may crash if DNS cache resolver concurrency settings are changed during live traffic

Last Modified: Apr 16, 2026

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

Known Affected Versions:
16.1.6.1, 17.5.1.5

Opened: Apr 01, 2026

Severity: 3-Major

Symptoms

TMM crashes with a SIGSEGV and then restarts.

Impact

Traffic is disrupted during a TMM restart, and the redundant unit fails over.

Conditions

- The DNS cache resolver is configured and processing queries. - A DNS cache-resolver object is changed, specifically a setting that alters max-concurrent-queries or max-concurrent-tcp. - Live DNS traffic is in progress when the change is applied.

Workaround

None

Fix Information

None

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips