diff --git a/packages/fxa-content-server/package.json b/packages/fxa-content-server/package.json
index 473c513727..9d137ee059 100644
--- a/packages/fxa-content-server/package.json
+++ b/packages/fxa-content-server/package.json
@@ -121,7 +121,7 @@
     "normalize.css": "8.0.1",
     "on-headers": "1.0.2",
     "postcss-cli": "11.0.0",
-    "postcss-loader": "4.2.0",
+    "postcss-loader": "8.1.1",
     "sass-loader": "^14.1.0",
     "serve-static": "^1.14.2",
     "source-map": "^0.7.3",
diff --git a/packages/fxa-settings/package.json b/packages/fxa-settings/package.json
index 7da5a3c129..1d7c74e8ec 100644
--- a/packages/fxa-settings/package.json
+++ b/packages/fxa-settings/package.json
@@ -161,7 +161,7 @@
     "mini-css-extract-plugin": "^2.8.0",
     "postcss": "^8.4.31",
     "postcss-flexbugs-fixes": "^5.0.2",
-    "postcss-loader": "^6.2.1",
+    "postcss-loader": "^8.1.1",
     "postcss-normalize": "^10.0.1",
     "postcss-preset-env": "^9.3.0",
     "prompts": "^2.4.2",
diff --git a/yarn.lock b/yarn.lock
index 9967e62f05..55c29bb619 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -30769,6 +30769,23 @@ __metadata:
   languageName: node
   linkType: hard
 
+"cosmiconfig@npm:^9.0.0":
+  version: 9.0.0
+  resolution: "cosmiconfig@npm:9.0.0"
+  dependencies:
+    env-paths: ^2.2.1
+    import-fresh: ^3.3.0
+    js-yaml: ^4.1.0
+    parse-json: ^5.2.0
+  peerDependencies:
+    typescript: ">=4.9.5"
+  peerDependenciesMeta:
+    typescript:
+      optional: true
+  checksum: a30c424b53d442ea0bdd24cb1b3d0d8687c8dda4a17ab6afcdc439f8964438801619cdb66e8e79f63b9caa3e6586b60d8bab9ce203e72df6c5e80179b971fe8f
+  languageName: node
+  linkType: hard
+
 "create-ecdh@npm:^4.0.0":
   version: 4.0.3
   resolution: "create-ecdh@npm:4.0.3"
@@ -33266,6 +33283,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"env-paths@npm:^2.2.1":
+  version: 2.2.1
+  resolution: "env-paths@npm:2.2.1"
+  checksum: 65b5df55a8bab92229ab2b40dad3b387fad24613263d103a97f91c9fe43ceb21965cd3392b1ccb5d77088021e525c4e0481adb309625d0cb94ade1d1fb8dc17e
+  languageName: node
+  linkType: hard
+
 "envinfo@npm:^7.7.3":
   version: 7.7.3
   resolution: "envinfo@npm:7.7.3"
@@ -37489,7 +37513,7 @@ fsevents@~2.1.1:
     postcss-assets: ^6.0.0
     postcss-cli: 11.0.0
     postcss-import: ^16.0.0
-    postcss-loader: 4.2.0
+    postcss-loader: 8.1.1
     prettier: ^2.3.1
     proxyquire: ^2.1.3
     request: ^2.88.2
@@ -38068,7 +38092,7 @@ fsevents@~2.1.1:
     postcss-assets: ^6.0.0
     postcss-flexbugs-fixes: ^5.0.2
     postcss-import: ^16.0.0
-    postcss-loader: ^6.2.1
+    postcss-loader: ^8.1.1
     postcss-normalize: ^10.0.1
     postcss-preset-env: ^9.3.0
     prompts: ^2.4.2
@@ -45255,7 +45279,7 @@ fsevents@~2.1.1:
   languageName: node
   linkType: hard
 
-"jiti@npm:^1.19.1":
+"jiti@npm:^1.19.1, jiti@npm:^1.20.0":
   version: 1.21.0
   resolution: "jiti@npm:1.21.0"
   bin:
@@ -53503,19 +53527,23 @@ fsevents@~2.1.1:
   languageName: node
   linkType: hard
 
-"postcss-loader@npm:4.2.0":
-  version: 4.2.0
-  resolution: "postcss-loader@npm:4.2.0"
+"postcss-loader@npm:8.1.1, postcss-loader@npm:^8.1.1":
+  version: 8.1.1
+  resolution: "postcss-loader@npm:8.1.1"
   dependencies:
-    cosmiconfig: ^7.0.0
-    klona: ^2.0.4
-    loader-utils: ^2.0.0
-    schema-utils: ^3.0.0
-    semver: ^7.3.4
+    cosmiconfig: ^9.0.0
+    jiti: ^1.20.0
+    semver: ^7.5.4
   peerDependencies:
+    "@rspack/core": 0.x || 1.x
     postcss: ^7.0.0 || ^8.0.1
-    webpack: ^4.0.0 || ^5.0.0
-  checksum: c45ec1ca1b1ca528f18fce32b00c4b7ae4fd5dec57b3766fbd0bd84cb911b538220e76f3c07e66a1d078d75b718c36764714ede080ca4440fb6f11774850de11
+    webpack: ^5.0.0
+  peerDependenciesMeta:
+    "@rspack/core":
+      optional: true
+    webpack:
+      optional: true
+  checksum: b09e230181ff70b374a3e265dc526302b9865e2697b5f9c4ff78dfeb716a3508f3247ed49c8ee6630dddfdf6df7d73556d6bd2eb165a00c48dba3a1bd01e3a2e
   languageName: node
   linkType: hard