Bug ID 425149: Avoid stalling connections

Last Modified: Nov 22, 2021

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

Known Affected Versions:
11.3.0, 11.4.0

Fixed In:
11.5.0, 11.4.0 HF3, 11.3.0 HF8

Opened: Jul 13, 2013

Severity: 2-Critical


A SIGABRT was occured likely due to somewhat low-memory conditions - the core stack trace is in umem allocator with all threads showing HSB attempting to allocate xfrags.


This may occur while the system is under DoS attack and unable to mitigate the attack. You may find that when enabling URL rate limiting, BIG-IP effectively denies access to a significant number of legitimate users, so use of this feature is limited under this attack.


enable ASM DoSL7.


This issue has no workaround at this time.

Fix Information

We fixed a memory leak that sometimes occurred during a DoS attack.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips