diff --git a/interpreter/binary/decode.ml b/interpreter/binary/decode.ml
index df6c9e63a9..d996a5f4b1 100644
--- a/interpreter/binary/decode.ml
+++ b/interpreter/binary/decode.ml
@@ -310,6 +310,7 @@ let memop s =
   let has_var = Int32.logand flags 0x40l <> 0l in
   let x = if has_var then at var s else Source.(0l @@ no_region) in
   let align = Int32.(to_int (logand flags 0x3fl)) in
+  require (align < 32) s pos "malformed memop alignment";
   let offset = u32 s in
   x, align, offset
 
diff --git a/test/core/align.wast b/test/core/align.wast
index 93064649d3..817a1dfb24 100644
--- a/test/core/align.wast
+++ b/test/core/align.wast
@@ -864,3 +864,120 @@
 (assert_trap (invoke "store" (i32.const 65532) (i64.const -1)) "out of bounds memory access")
 ;; No memory was changed
 (assert_return (invoke "load" (i32.const 65532)) (i32.const 0))
+
+;; Test invalid alignment values that may cause overflow when parsed.
+;; These use the binary format, because it stores alignment as a base-2 exponent.
+
+;; Signed 32-bit overflow
+(assert_invalid
+  (module binary 
+    "\00asm" "\01\00\00\00"
+    "\01\04\01\60\00\00"       ;; Type section: 1 type
+    "\03\02\01\00"             ;; Function section: 1 function
+    "\05\03\01\00\01"          ;; Memory section: 1 memory
+    "\0a\0a\01"                ;; Code section: 1 function
+
+    ;; function 0
+    "\08\00"
+    "\41\00"                   ;; i32.const 0
+    "\28\1f\00"                ;; i32.load offset=0 align=2**31
+    "\1a"                      ;; drop
+    "\0b"                      ;; end
+  )
+  "alignment must not be larger than natural"
+)
+
+;; Unsigned 32-bit overflow
+(assert_malformed
+  (module binary 
+    "\00asm" "\01\00\00\00"
+    "\01\04\01\60\00\00"       ;; Type section: 1 type
+    "\03\02\01\00"             ;; Function section: 1 function
+    "\05\03\01\00\01"          ;; Memory section: 1 memory
+    "\0a\0a\01"                ;; Code section: 1 function
+
+    ;; function 0
+    "\08\00"
+    "\41\00"                   ;; i32.const 0
+    "\28\20\00"                ;; i32.load offset=0 align=2**32
+    "\1a"                      ;; drop
+    "\0b"                      ;; end
+  )
+  "malformed memop alignment"
+)
+
+;; 32-bit out of range
+(assert_malformed
+  (module binary 
+    "\00asm" "\01\00\00\00"
+    "\01\04\01\60\00\00"       ;; Type section: 1 type
+    "\03\02\01\00"             ;; Function section: 1 function
+    "\05\03\01\00\01"          ;; Memory section: 1 memory
+    "\0a\0a\01"                ;; Code section: 1 function
+
+    ;; function 0
+    "\08\00"
+    "\41\00"                   ;; i32.const 0
+    "\28\21\00"                ;; i32.load offset=0 align=2**33
+    "\1a"                      ;; drop
+    "\0b"                      ;; end
+  )
+  "malformed memop alignment"
+)
+
+;; Signed 64-bit overflow
+(assert_malformed
+  (module binary 
+    "\00asm" "\01\00\00\00"
+    "\01\04\01\60\00\00"       ;; Type section: 1 type
+    "\03\02\01\00"             ;; Function section: 1 function
+    "\05\03\01\00\01"          ;; Memory section: 1 memory
+    "\0a\0a\01"                ;; Code section: 1 function
+
+    ;; function 0
+    "\08\00"
+    "\41\00"                   ;; i32.const 0
+    "\28\3f\00"                ;; i32.load offset=0 align=2**63
+    "\1a"                      ;; drop
+    "\0b"                      ;; end
+  )
+  "malformed memop alignment"
+)
+
+;; Unsigned 64-bit overflow
+(assert_invalid
+  (module binary 
+    "\00asm" "\01\00\00\00"
+    "\01\04\01\60\00\00"       ;; Type section: 1 type
+    "\03\02\01\00"             ;; Function section: 1 function
+    "\05\03\01\00\01"          ;; Memory section: 1 memory
+    "\0a\0a\01"                ;; Code section: 1 function
+
+    ;; function 0
+    "\08\00"
+    "\41\00"                   ;; i32.const 0
+    "\28\40\00"                ;; i32.load offset=0 align=2**64 (parsed as align=0, memidx present)
+    "\1a"                      ;; drop
+    "\0b"                      ;; end
+  )
+  "type mismatch"
+)
+
+;; 64-bit out of range
+(assert_invalid
+  (module binary 
+    "\00asm" "\01\00\00\00"
+    "\01\04\01\60\00\00"       ;; Type section: 1 type
+    "\03\02\01\00"             ;; Function section: 1 function
+    "\05\03\01\00\01"          ;; Memory section: 1 memory
+    "\0a\0a\01"                ;; Code section: 1 function
+
+    ;; function 0
+    "\08\00"
+    "\41\00"                   ;; i32.const 0
+    "\28\41\00"                ;; i32.load offset=0 align=2**65 (parsed as align=1, memidx present)
+    "\1a"                      ;; drop
+    "\0b"                      ;; end
+  )
+  "type mismatch"
+)
diff --git a/test/core/run.py b/test/core/run.py
index bdc2a447af..21036065d6 100755
--- a/test/core/run.py
+++ b/test/core/run.py
@@ -19,6 +19,7 @@
 parser.add_argument("--wasm", metavar="<wasm-command>", default=os.path.join(interpDir, "wasm"))
 parser.add_argument("--js", metavar="<js-command>")
 parser.add_argument("--generate-js-only", action='store_true')
+parser.add_argument("--failfast", action='store_true')
 parser.add_argument("--out", metavar="<out-dir>", default=outputDir)
 parser.add_argument("file", nargs='*')
 arguments = parser.parse_args()
@@ -120,4 +121,4 @@ def _runTestFile(self, inputPath):
   for fileName in inputFiles:
     testName = 'test ' + os.path.basename(fileName)
     setattr(RunTests, testName, lambda self, file=fileName: self._runTestFile(file))
-  unittest.main()
+  unittest.main(failfast=arguments.failfast)
diff --git a/test/meta/Makefile b/test/meta/Makefile
index 20e9adb2f5..05a42beb79 100644
--- a/test/meta/Makefile
+++ b/test/meta/Makefile
@@ -1,10 +1,10 @@
 SHARED_MEM=false
 
 # SpiderMonkey shell
-JSSHELL=~/mozilla-central/js/src/build-debug/dist/bin/js -e 'const WITH_SHARED_MEMORY=$(SHARED_MEM);' -f common.js
+#JSSHELL=~/mozilla-central/js/src/build-debug/dist/bin/js -e 'const WITH_SHARED_MEMORY=$(SHARED_MEM);' -f common.js
 
 # Node.js
-#JSSHELL=./noderun.sh $(SHARED_MEM)
+JSSHELL=./noderun.sh $(SHARED_MEM)
 
 TARGETDIR=../core