From bf3f407b5fffac1d74142c52fa28fda91a542f8f Mon Sep 17 00:00:00 2001
From: Kusal Kithul-Godage <git@kusal.io>
Date: Tue, 9 Jan 2024 15:48:35 +1100
Subject: [PATCH] WW-5352 Ensure allowlist is cleared if in unexpected state

---
 .../struts2/interceptor/parameter/ParametersInterceptor.java  | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/core/src/main/java/org/apache/struts2/interceptor/parameter/ParametersInterceptor.java b/core/src/main/java/org/apache/struts2/interceptor/parameter/ParametersInterceptor.java
index 08c956f21..f1651cd86 100644
--- a/core/src/main/java/org/apache/struts2/interceptor/parameter/ParametersInterceptor.java
+++ b/core/src/main/java/org/apache/struts2/interceptor/parameter/ParametersInterceptor.java
@@ -219,6 +219,10 @@ public class ParametersInterceptor extends MethodFilterInterceptor {
         Map<String, Parameter> acceptableParameters;
         ValueStack newStack;
         try {
+            if (!threadAllowlist.getAllowlist().isEmpty()) {
+                LOG.error("Thread allowlist was utilised but not cleared", new IllegalStateException());
+                threadAllowlist.clearAllowlist();
+            }
             acceptableParameters = toAcceptableParameters(parameters, action); // Side-effect: Allowlist required types
 
             newStack = toNewStack(stack);