Virtual Service Traffic Flagged by WAF Due to "Time limit exceeded when processing rules max_execution_time=50"

Products

• VMware Avi Load Balancer

Issue/Introduction

-The Web Application Firewall (WAF) log the following error when processing requests:

 

Time limit exceeded when processing rules max_execution_time=50

 

-This indicates that WAF rule execution exceeded the configured maximum processing time. The request outcome depends on the WAF policy mode and the configured failure_mode:

 

• Detection Mode → Requests are always allowed but logged as FLAGGED.

• Enforcement Mode →

  • fail open (default): Request allowed and logged as FLAGGED.

  • fail closed: Request blocked with 403 Forbidden and logged as REJECTED.

 

-To check the "max_execution_time".

-To check the current WAF policy mode and failure mode.

 

Environment

All environment

Cause

-The error occurs when WAF processing exceeds the configured limit (max_execution_time=50). Contributing factors may include:

• Large or complex request payloads

• Regex-heavy or computationally expensive WAF rules

• High concurrent traffic

• Inadequate VM resources (CPU, memory, or CPU pinning)

-Once the execution time is exceeded, WAF stops further rule evaluation and applies the behavior defined by policy mode and failure_mode.

Resolution

-Verify WAF Policy Settings

• Confirm the configured failure_mode matches your enforcement requirements.