diff --git a/package-lock.json b/package-lock.json
index 586958a35..814d53b87 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4075,9 +4075,9 @@
 			}
 		},
 		"node_modules/@webref/css": {
-			"version": "6.18.1",
-			"resolved": "https://registry.npmjs.org/@webref/css/-/css-6.18.1.tgz",
-			"integrity": "sha512-bHkYRYhhSNzrPBAzn2KKnWiG6m5MBlJEx/r/c0nW2bTURptdBt2jjvr09e6wKoiLSH8FCJ/CydCRTM+XnwiQvg==",
+			"version": "6.20.3",
+			"resolved": "https://registry.npmjs.org/@webref/css/-/css-6.20.3.tgz",
+			"integrity": "sha512-Fa+MWaQ9lhK+uVqqwTbeZ0FhlNKJemOj43WhFUFoSGXDtkH0CGrnl2VNRJ50qC1x8r4kDzNAxZKbncusRANmPA==",
 			"dev": true,
 			"license": "MIT",
 			"peerDependencies": {
@@ -9300,7 +9300,7 @@
 			],
 			"license": "MIT-0",
 			"devDependencies": {
-				"@webref/css": "^6.18.1",
+				"@webref/css": "^6.20.3",
 				"css-tree": "^3.1.0"
 			},
 			"engines": {
@@ -9601,7 +9601,7 @@
 			"devDependencies": {
 				"@csstools/postcss-bundler": "*",
 				"@csstools/postcss-tape": "*",
-				"@webref/css": "^6.18.1"
+				"@webref/css": "^6.20.3"
 			},
 			"engines": {
 				"node": ">=18"
diff --git a/packages/css-syntax-patches-for-csstree/package.json b/packages/css-syntax-patches-for-csstree/package.json
index f763abf40..dd234b044 100644
--- a/packages/css-syntax-patches-for-csstree/package.json
+++ b/packages/css-syntax-patches-for-csstree/package.json
@@ -39,7 +39,7 @@
 		"postcss": "^8.4"
 	},
 	"devDependencies": {
-		"@webref/css": "^6.18.1",
+		"@webref/css": "^6.20.3",
 		"css-tree": "^3.1.0"
 	},
 	"scripts": {
diff --git a/plugin-packs/postcss-preset-env/package.json b/plugin-packs/postcss-preset-env/package.json
index 63cdfa6e8..aedd1e1c9 100644
--- a/plugin-packs/postcss-preset-env/package.json
+++ b/plugin-packs/postcss-preset-env/package.json
@@ -122,7 +122,7 @@
 	"devDependencies": {
 		"@csstools/postcss-bundler": "*",
 		"@csstools/postcss-tape": "*",
-		"@webref/css": "^6.18.1"
+		"@webref/css": "^6.20.3"
 	},
 	"scripts": {
 		"prebuild": "node ./scripts/generate-plugins-data.mjs && eslint --fix ./src/plugins/*.mjs",