diff --git a/lib/rules/declaration-property-value-no-unknown/index.js b/lib/rules/declaration-property-value-no-unknown/index.js
index 97f8c9f80b..0ae887c33c 100644
--- a/lib/rules/declaration-property-value-no-unknown/index.js
+++ b/lib/rules/declaration-property-value-no-unknown/index.js
@@ -84,10 +84,12 @@ const rule = (primary, secondaryOptions) => {
 
 			if (isPropIgnored(prop, value)) return;
 
+			let cssTreeValueNode;
+
 			try {
-				const valueNode = parse(value, { context: 'value' });
+				cssTreeValueNode = parse(value, { context: 'value' });
 
-				if (containsUnsupportedMathFunction(valueNode)) return;
+				if (containsUnsupportedMathFunction(cssTreeValueNode)) return;
 			} catch (e) {
 				result.warn(`Cannot parse property value "${value}"`, {
 					node: decl,
@@ -97,7 +99,7 @@ const rule = (primary, secondaryOptions) => {
 				return;
 			}
 
-			const { error } = forkedLexer.matchProperty(prop, value);
+			const { error } = forkedLexer.matchProperty(prop, cssTreeValueNode);
 
 			if (!error) return;
 
diff --git a/patches/@types+css-tree+2.0.1.patch b/patches/@types+css-tree+2.0.1.patch
index 4c1fbcb5c7..7c7c0910ee 100644
--- a/patches/@types+css-tree+2.0.1.patch
+++ b/patches/@types+css-tree+2.0.1.patch
@@ -17,7 +17,7 @@ index 2e4ed18..7f096c6 100755
 +};
 +
 +declare class Lexer {
-+    matchProperty(propertyName: string, value: string): MatchResult;
++    matchProperty(propertyName: string, value: CssNode | string): MatchResult;
 +}
 +
 +export function fork(extension: Record<string, Record<string, string>>): { lexer: Lexer };