diff --git a/packages/fxa-content-server/package.json b/packages/fxa-content-server/package.json
index 3fd708d3f3..147383ca20 100644
--- a/packages/fxa-content-server/package.json
+++ b/packages/fxa-content-server/package.json
@@ -173,7 +173,7 @@
     "ts-node": "^10.0.0",
     "upng-js": "2.1.0",
     "url-loader": "4.1.1",
-    "webpack-dev-middleware": "^4.3.0",
+    "webpack-dev-middleware": "^5.0.0",
     "xmlhttprequest": "git://github.com/mozilla-fxa/node-XMLHttpRequest.git#onerror",
     "yargs": "^17.0.1"
   },
diff --git a/yarn.lock b/yarn.lock
index 4295a70095..e521819b23 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -18644,7 +18644,7 @@ fsevents@~2.1.1:
     webcrypto-liner: "git://github.com/mozilla-fxa/webcrypto-liner.git#6b3ad971b3b1f0d4da3855c6ceee9b3afa9f0eeb"
     webpack: ^4.41.2
     webpack-cli: ^4.7.0
-    webpack-dev-middleware: ^4.3.0
+    webpack-dev-middleware: ^5.0.0
     xmlhttprequest: "git://github.com/mozilla-fxa/node-XMLHttpRequest.git#onerror"
     yargs: ^17.0.1
   languageName: unknown
@@ -26101,7 +26101,14 @@ fsevents@~2.1.1:
   languageName: node
   linkType: hard
 
-"mime-types@npm:^2.1.12, mime-types@npm:^2.1.27, mime-types@npm:^2.1.30, mime-types@npm:~2.1.17, mime-types@npm:~2.1.19, mime-types@npm:~2.1.24":
+"mime-db@npm:1.48.0":
+  version: 1.48.0
+  resolution: "mime-db@npm:1.48.0"
+  checksum: 346d5df2ff2f501bdeff07e88a28d205f9cd27bccd3b8604847d3aee6ce73d4ecf88e943bbbce46c167d404487f46cdf09d57354c51b6f08a4d5833bcaafa59f
+  languageName: node
+  linkType: hard
+
+"mime-types@npm:^2.1.12, mime-types@npm:^2.1.27, mime-types@npm:~2.1.17, mime-types@npm:~2.1.19, mime-types@npm:~2.1.24":
   version: 2.1.30
   resolution: "mime-types@npm:2.1.30"
   dependencies:
@@ -26110,6 +26117,15 @@ fsevents@~2.1.1:
   languageName: node
   linkType: hard
 
+"mime-types@npm:^2.1.31":
+  version: 2.1.31
+  resolution: "mime-types@npm:2.1.31"
+  dependencies:
+    mime-db: 1.48.0
+  checksum: 0373e58e3826802e462cf0c180ca5556fd0990acaf123d421d5f8643f0ca61d2126ea57eb6f4ba96f9ef07d3e627c06261825418a6549b0671261cc1bb4219b4
+  languageName: node
+  linkType: hard
+
 "mime@npm:1.4.1":
   version: 1.4.1
   resolution: "mime@npm:1.4.1"
@@ -37661,19 +37677,19 @@ typescript@^4.2.4:
   languageName: node
   linkType: hard
 
-"webpack-dev-middleware@npm:^4.3.0":
-  version: 4.3.0
-  resolution: "webpack-dev-middleware@npm:4.3.0"
+"webpack-dev-middleware@npm:^5.0.0":
+  version: 5.0.0
+  resolution: "webpack-dev-middleware@npm:5.0.0"
   dependencies:
     colorette: ^1.2.2
     mem: ^8.1.1
     memfs: ^3.2.2
-    mime-types: ^2.1.30
+    mime-types: ^2.1.31
     range-parser: ^1.2.1
     schema-utils: ^3.0.0
   peerDependencies:
     webpack: ^4.0.0 || ^5.0.0
-  checksum: 1b516cfcf52e5ecadd20c85887bef3e8db3be17aab37823413a68f1926fe12fdd5ba01ff06c045c9516709369712d02e46136fedb25cc78c5e3453c141be2b47
+  checksum: b6ff8fed985e89072ef84357ac8d1778a326de3f87cd60b8ab719565223d3949e06778fee434bae8e53ebd4af288de4561cbba4970f1872d70f38bdfc4b69d86
   languageName: node
   linkType: hard