diff --git a/e2e-package-managers/yarn/package.json b/e2e-package-managers/yarn/package.json
index 54fa2b642..1aaaf0d42 100644
--- a/e2e-package-managers/yarn/package.json
+++ b/e2e-package-managers/yarn/package.json
@@ -4,7 +4,7 @@
 	"private": true,
 	"description": "Can you use yarn with our plugins?",
 	"devDependencies": {
-		"postcss": "^8.5.10",
+		"postcss": "^8.5.12",
 		"postcss-preset-env": "^11.2.1"
 	},
 	"volta": {
diff --git a/e2e/browserslist/package-json/package.json b/e2e/browserslist/package-json/package.json
index e6f3f14d1..b5805014a 100644
--- a/e2e/browserslist/package-json/package.json
+++ b/e2e/browserslist/package-json/package.json
@@ -7,7 +7,7 @@
 		"test": "BROWSERSLIST_ENV=development node ./index.mjs && BROWSERSLIST_ENV=production node ./index.mjs && BROWSERSLIST_ENV=legacy-edge node ./index.mjs && node ./use-plugin-option.mjs"
 	},
 	"devDependencies": {
-		"postcss": "^8.5.10",
+		"postcss": "^8.5.12",
 		"postcss-preset-env": "file:../../../plugin-packs/postcss-preset-env"
 	},
 	"browserslist": {
diff --git a/e2e/package-lock.json b/e2e/package-lock.json
index c26dd9150..8b303eb9a 100644
--- a/e2e/package-lock.json
+++ b/e2e/package-lock.json
@@ -71,7 +71,7 @@
 				"@csstools/postcss-text-decoration-shorthand": "^5.0.3",
 				"@csstools/postcss-trigonometric-functions": "^5.0.2",
 				"@csstools/postcss-unset-value": "^5.0.0",
-				"autoprefixer": "^10.4.24",
+				"autoprefixer": "^10.5.0",
 				"browserslist": "^4.28.1",
 				"css-blank-pseudo": "^8.0.1",
 				"css-has-pseudo": "^8.0.0",
@@ -107,7 +107,7 @@
 				"@csstools/pack-test": "*",
 				"@csstools/postcss-bundler": "*",
 				"@csstools/postcss-tape": "*",
-				"@webref/css": "8.5.3"
+				"@webref/css": "8.5.4"
 			},
 			"engines": {
 				"node": ">=20.19.0"
@@ -240,7 +240,7 @@
 			"name": "@csstools/e2e--browserslist--package-json",
 			"version": "0.0.0",
 			"devDependencies": {
-				"postcss": "^8.5.10",
+				"postcss": "^8.5.12",
 				"postcss-preset-env": "file:../../../plugin-packs/postcss-preset-env"
 			}
 		},
@@ -1735,9 +1735,9 @@
 			}
 		},
 		"node_modules/postcss": {
-			"version": "8.5.10",
-			"resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.10.tgz",
-			"integrity": "sha512-pMMHxBOZKFU6HgAZ4eyGnwXF/EvPGGqUr0MnZ5+99485wwW41kW91A4LOGxSHhgugZmSChL5AlElNdwlNgcnLQ==",
+			"version": "8.5.12",
+			"resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.12.tgz",
+			"integrity": "sha512-W62t/Se6rA0Az3DfCL0AqJwXuKwBeYg6nOaIgzP+xZ7N5BFCI7DYi1qs6ygUYT6rvfi6t9k65UMLJC+PHZpDAA==",
 			"funding": [
 				{
 					"type": "opencollective",
@@ -2733,7 +2733,7 @@
 			"name": "@csstools/e2e--webpack--bundle-through",
 			"version": "0.0.0",
 			"dependencies": {
-				"postcss": "^8.5.10",
+				"postcss": "^8.5.12",
 				"postcss-preset-env": "file:../../../plugin-packs/postcss-preset-env",
 				"webpack": "^5.106.2",
 				"webpack-cli": "^7.0.0"
@@ -2744,7 +2744,7 @@
 			"version": "0.0.0",
 			"dependencies": {
 				"css-loader": "^7.1.3",
-				"postcss": "^8.5.10",
+				"postcss": "^8.5.12",
 				"postcss-loader": "^8.2.1",
 				"postcss-preset-env": "file:../../../plugin-packs/postcss-preset-env",
 				"style-loader": "^4.0.0",
diff --git a/e2e/webpack/bundle-through/package.json b/e2e/webpack/bundle-through/package.json
index 794c0281f..a19f89e42 100644
--- a/e2e/webpack/bundle-through/package.json
+++ b/e2e/webpack/bundle-through/package.json
@@ -9,7 +9,7 @@
 		"test": "node ./dist/bundle-from-mjs.cjs && node ./dist/bundle-from-cjs.cjs "
 	},
 	"dependencies": {
-		"postcss": "^8.5.10",
+		"postcss": "^8.5.12",
 		"webpack": "^5.106.2",
 		"webpack-cli": "^7.0.0",
 		"postcss-preset-env": "file:../../../plugin-packs/postcss-preset-env"
diff --git a/e2e/webpack/postcss-loader/package.json b/e2e/webpack/postcss-loader/package.json
index 558e36396..5297ef9da 100644
--- a/e2e/webpack/postcss-loader/package.json
+++ b/e2e/webpack/postcss-loader/package.json
@@ -8,7 +8,7 @@
 		"build": "webpack --config webpack.config.js"
 	},
 	"dependencies": {
-		"postcss": "^8.5.10",
+		"postcss": "^8.5.12",
 		"webpack": "^5.106.2",
 		"webpack-cli": "^7.0.0",
 		"postcss-loader": "^8.2.1",
diff --git a/sites/package-lock.json b/sites/package-lock.json
index e8f29d594..d6f08094a 100644
--- a/sites/package-lock.json
+++ b/sites/package-lock.json
@@ -7163,9 +7163,9 @@
 			}
 		},
 		"node_modules/postcss": {
-			"version": "8.5.10",
-			"resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.10.tgz",
-			"integrity": "sha512-pMMHxBOZKFU6HgAZ4eyGnwXF/EvPGGqUr0MnZ5+99485wwW41kW91A4LOGxSHhgugZmSChL5AlElNdwlNgcnLQ==",
+			"version": "8.5.12",
+			"resolved": "https://registry.npmjs.org/postcss/-/postcss-8.5.12.tgz",
+			"integrity": "sha512-W62t/Se6rA0Az3DfCL0AqJwXuKwBeYg6nOaIgzP+xZ7N5BFCI7DYi1qs6ygUYT6rvfi6t9k65UMLJC+PHZpDAA==",
 			"dev": true,
 			"funding": [
 				{
@@ -9541,7 +9541,7 @@
 				"luxon": "^3.7.2",
 				"markdown-it": "^14.1.0",
 				"npm-run-all": "^4.1.5",
-				"postcss": "^8.5.10",
+				"postcss": "^8.5.12",
 				"postcss-cli": "^11.0.1",
 				"postcss-preset-env": "^11.2.1",
 				"rollup": "^4.60.2",
diff --git a/sites/postcss-preset-env/package.json b/sites/postcss-preset-env/package.json
index d7adf0899..3fc06cc32 100644
--- a/sites/postcss-preset-env/package.json
+++ b/sites/postcss-preset-env/package.json
@@ -77,7 +77,7 @@
 		"luxon": "^3.7.2",
 		"markdown-it": "^14.1.0",
 		"npm-run-all": "^4.1.5",
-		"postcss": "^8.5.10",
+		"postcss": "^8.5.12",
 		"postcss-cli": "^11.0.1",
 		"postcss-preset-env": "^11.2.1",
 		"rollup": "^4.60.2",