Bug ID 597966: ARP/neighbor cache nexthop object can be freed while still referenced by another structure

Last Modified: Apr 28, 2025

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

Known Affected Versions:
11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.5.3 HF2, 11.5.4, 11.5.4 HF1, 11.5.4 HF2, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5, 11.6.0 HF6, 11.6.0 HF7, 11.6.0 HF8, 11.6.1, 11.6.1 HF1

Fixed In:
11.6.1 HF2, 11.5.4 HF3

Opened: Jun 08, 2016

Severity: 2-Critical

Related Article: K82090640

Symptoms

Use after free or double-free of the nexthop object may cause memory corruption or TMM core.

Impact

The BIG-IP dataplane might crash. This is a very timing/memory-usage-dependent issue.

Conditions

This can happen if the server-side connection establishment takes some time to complete, creating a large enough time window where the nexthop object might be freed.

Workaround

None.

Fix Information

Management of nexthop object reference counting is more consistent.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips