diff --git a/src/parser/jsonParser.ts b/src/parser/jsonParser.ts
index 33e3b80d..14fd3876 100644
--- a/src/parser/jsonParser.ts
+++ b/src/parser/jsonParser.ts
@@ -718,7 +718,7 @@ function validate(n: ASTNode | undefined, schema: JSONSchema, validationResult:
 
 		if (isString(schema.pattern)) {
 			const regex = extendedRegExp(schema.pattern);
-			if (!(regex?.test(node.value))) {
+			if (regex && !(regex.test(node.value))) {
 				validationResult.problems.push({
 					location: { offset: node.offset, length: node.length },
 					message: schema.patternErrorMessage || schema.errorMessage || l10n.t('String does not match the pattern of "{0}".', schema.pattern)
diff --git a/src/test/parser.test.ts b/src/test/parser.test.ts
index e6cf4e09..ca1a92fb 100644
--- a/src/test/parser.test.ts
+++ b/src/test/parser.test.ts
@@ -609,6 +609,18 @@ suite('JSON Parser', () => {
 
 		assert.strictEqual(semanticErrors!.length, 0);
 
+		semanticErrors = validate2(jsonDoc, textDoc, {
+			type: 'object',
+			properties: {
+				"one": {
+					type: 'string',
+					pattern: '*+ (invalid pattern)',
+				}
+			}
+		});
+
+		assert.strictEqual(semanticErrors!.length, 0);
+
 		semanticErrors = validate2(jsonDoc, textDoc, {
 			type: 'object',
 			properties: {