diff --git a/.clusterfuzzlite/build.sh b/.clusterfuzzlite/build.sh
index e173679f..f171b418 100755
--- a/.clusterfuzzlite/build.sh
+++ b/.clusterfuzzlite/build.sh
@@ -29,7 +29,7 @@ source ../helper.sh
 
 if [[ "$SANITIZER" == "address" ]]; then
 	# Asan
-	./configure --enable-asan
+	./configure --enable-werror --enable-asan
 	make -sj4
 	cp ../run/john "$OUT"/
 
@@ -44,7 +44,7 @@ fi
 
 if [[ "$SANITIZER" == "undefined" ]]; then
 	# Ubsan
-	./configure --enable-ubsan
+	./configure --enable-werror --enable-ubsan
 	make -sj4
 	cp ../run/john "$OUT"/
 
diff --git a/.github/actions/spelling/expect.txt b/.github/actions/spelling/expect.txt
index df11451f..e96289f3 100644
--- a/.github/actions/spelling/expect.txt
+++ b/.github/actions/spelling/expect.txt
@@ -266,6 +266,7 @@ vmactions
 vnc
 vncpcap
 vpc
+werror
 wordlist
 worg
 woria
diff --git a/deploy/Mac_ARM-Delivery.yml b/deploy/Mac_ARM-Delivery.yml
index d59a3fd3..51b78b3f 100644
--- a/deploy/Mac_ARM-Delivery.yml
+++ b/deploy/Mac_ARM-Delivery.yml
@@ -29,7 +29,7 @@ macOS_task:
 
   env:
     CIRRUS_CLONE_DEPTH: "10"
-    BUILD_OPS: "--build=aarch64-apple-darwin"
+    BUILD_OPS: "--build=aarch64-apple-darwin --enable-werror"
     CC: "clang"
     MAKE_FLAGS: "-sj4"
     TARGET_ARCH: "macOS ARM"
diff --git a/deploy/Windows-Delivery.yml b/deploy/Windows-Delivery.yml
index f642e2d2..fa626048 100644
--- a/deploy/Windows-Delivery.yml
+++ b/deploy/Windows-Delivery.yml
@@ -87,8 +87,8 @@ steps:
       #    + CategoryInfo          : NotSpecified: (ar: creating aes.a:String) [], RemoteException
       #    + FullyQualifiedErrorId : NativeCommandError
       # ####
-      $EXE_NORMAL = "--disable-native-tests"
-      $EXE_NO_OMP = "--disable-native-tests --disable-openmp"
+      $EXE_NORMAL = "--enable-werror --disable-native-tests"
+      $EXE_NO_OMP = "--enable-werror --disable-native-tests --disable-openmp"
 
       # CPU (OMP and extensions fallback)
       shell "./configure $EXE_NO_OMP --enable-simd=avx                                                                                                                                                   && make -s clean && make -sj2 2>&1 && make -s strip && mv ../run/john ../run/john-avx"