diff --git a/tests/wpt/meta/MANIFEST.json b/tests/wpt/meta/MANIFEST.json
index 3dc39e93a10..06c1af4f347 100644
--- a/tests/wpt/meta/MANIFEST.json
+++ b/tests/wpt/meta/MANIFEST.json
@@ -521535,7 +521535,7 @@
         []
        ],
        "executorservo.py": [
-        "7b0a64a60489f91fe2d2ec92c69118c0b5b1b8c0",
+        "d983cf048ed6dfe1c07fdcac4f3465f116a00c58",
         []
        ],
        "executorservodriver.py": [
diff --git a/tests/wpt/tests/tools/wptrunner/wptrunner/executors/executorservo.py b/tests/wpt/tests/tools/wptrunner/wptrunner/executors/executorservo.py
index 7b0a64a6048..d983cf048ed 100644
--- a/tests/wpt/tests/tools/wptrunner/wptrunner/executors/executorservo.py
+++ b/tests/wpt/tests/tools/wptrunner/wptrunner/executors/executorservo.py
@@ -173,7 +173,10 @@ class ServoTestharnessExecutor(ServoExecutor):
         prefix = "ALERT: RESULT: "
         decoded_line = line.decode("utf8", "replace")
         if decoded_line.startswith(prefix):
-            self.result_data = json.loads(decoded_line[len(prefix):])
+            try:
+                self.result_data = json.loads(decoded_line[len(prefix):])
+            except json.JSONDecodeError as error:
+                self.logger.error(f"Could not process test output JSON: {error}")
             self.result_flag.set()
         else:
             ServoExecutor.on_output(self, line)