diff --git a/packages/@n8n/nodes-langchain/nodes/Guardrails/actions/checks/pii.ts b/packages/@n8n/nodes-langchain/nodes/Guardrails/actions/checks/pii.ts
index 9d5c6be649a..9a3acd5d557 100644
--- a/packages/@n8n/nodes-langchain/nodes/Guardrails/actions/checks/pii.ts
+++ b/packages/@n8n/nodes-langchain/nodes/Guardrails/actions/checks/pii.ts
@@ -7,7 +7,8 @@
  * schema for entity selection, output/result structures, and the async guardrail
  * check_fn for runtime enforcement.
  */
-import { safeRegex } from 'n8n-workflow';
+import { safeInternalRegex, safeUserRegex } from 'n8n-workflow';
+import type { RegexEngine } from 'n8n-workflow';
 
 import { parseRegex } from '../../helpers/common';
 import type { CreateCheckFn, CustomRegex } from '../types';
@@ -223,10 +224,14 @@ function detectPii(text: string, config: PIIConfig): PiiDetectionResult {
 	const grouped: Record<string, string[]> = {};
 	const analyzerResults: PiiAnalyzerResult[] = [];
 
-	const matchAgainstPattern = (name: string, literal: { source: string; flags: string }) => {
+	const matchAgainstPattern = (
+		name: string,
+		literal: { source: string; flags: string },
+		engine: RegexEngine = safeInternalRegex,
+	) => {
 		// make sure to add the global flag to the regex, otherwise while() will never end
 		const flags = literal.flags.includes('g') ? literal.flags : literal.flags + 'g';
-		const matches = safeRegex.matchAll(literal.source, text, flags);
+		const matches = engine.matchAll(literal.source, text, flags);
 		for (const match of matches) {
 			if (match.index === undefined) continue;
 
@@ -256,7 +261,7 @@ function detectPii(text: string, config: PIIConfig): PiiDetectionResult {
 	}
 	if (config.customRegex?.length) {
 		for (const regex of config.customRegex) {
-			matchAgainstPattern(regex.name, parseRegex(regex.value));
+			matchAgainstPattern(regex.name, parseRegex(regex.value), safeUserRegex);
 		}
 	}
 
diff --git a/packages/@n8n/nodes-langchain/nodes/Guardrails/actions/checks/secretKeys.ts b/packages/@n8n/nodes-langchain/nodes/Guardrails/actions/checks/secretKeys.ts
index 470df64d37a..df0142f7691 100644
--- a/packages/@n8n/nodes-langchain/nodes/Guardrails/actions/checks/secretKeys.ts
+++ b/packages/@n8n/nodes-langchain/nodes/Guardrails/actions/checks/secretKeys.ts
@@ -6,7 +6,7 @@
  * recognition, and a guardrail check_fn for runtime enforcement.
  */
 
-import { safeInternalRegex } from 'n8n-workflow';
+import { safeUserRegex } from 'n8n-workflow';
 
 import type { CreateCheckFn, GuardrailResult } from '../types';
 
@@ -187,7 +187,7 @@ function isSecretCandidate(
 	if (customRegex) {
 		for (const pattern of customRegex) {
 			try {
-				if (safeInternalRegex.test(pattern, s)) {
+				if (safeUserRegex.test(pattern, s)) {
 					return true;
 				}
 			} catch {