Last Modified: Oct 16, 2026
Affected Product(s):
BIG-IP (all modules)
Fixed In:
21.1.0.3, 17.5.1.10, 17.1.3.6
Opened: Jun 21, 2024 Severity: 3-Major
When processing a response to a monitor request, bigd performs pattern matching on the buffer to identify the matching string, drain string, and response code. If the response requires multiple recv() operations, bigd re-applies the regex to the entire buffer upon re-entering, leading to wasted cycles. This inefficiency can quickly result in high CPU usage if the server responds with a large message that does not contain the expected pattern. To mitigate this, the regex operation should be optimised to run in streaming mode, thereby reducing CPU load in such scenarios.
This may lead to high CPU utilisation.
This issue occurs when the server responds to monitor requests with a large response that does not match the expected recv string.
Not applicable
None