diff --git a/Wappalyzer/Wappalyzer.py b/Wappalyzer/Wappalyzer.py
index 8169048..f0036a0 100644
--- a/Wappalyzer/Wappalyzer.py
+++ b/Wappalyzer/Wappalyzer.py
@@ -7,6 +7,7 @@
 import os
 import pathlib
 import requests
+import soupsieve as sv
 
 from datetime import datetime, timedelta
 from typing import Optional
@@ -16,6 +17,14 @@
 
 logger = logging.getLogger(name="python-Wappalyzer")
 
+def is_valid_selector(sel):
+	try:
+		sv.compile(sel)
+	except (sv.SelectorSyntaxError, NotImplementedError):
+		logger.debug("Broken Selector:",sel)
+		return False
+	return True
+
 class WappalyzerError(Exception):
     # unused for now
     """
@@ -219,23 +228,24 @@ def _has_technology(self, tech_fingerprint: Fingerprint, webpage: IWebPage) -> b
         #           - "text": "regex": check if the .innerText property of the element that matches the css selector matches the regex (with version extraction).
         #           - "attributes": {dict from attr name to regex}: check if the attribute value of the element that matches the css selector matches the regex (with version extraction).
         for selector in tech_fingerprint.dom:
-            for item in webpage.select(selector.selector):
-                if selector.exists:
-                    self._set_detected_app(webpage.url, tech_fingerprint, 'dom', Pattern(string=selector.selector), value='')
-                    has_tech = True
-                if selector.text:
-                    for pattern in selector.text:
-                        if pattern.regex.search(item.inner_html):
-                            self._set_detected_app(webpage.url, tech_fingerprint, 'dom', pattern, value=item.inner_html)
-                            has_tech = True
-                if selector.attributes:
-                    for attrname, patterns in list(selector.attributes.items()):
-                        _content = item.attributes.get(attrname)
-                        if _content:
-                            for pattern in patterns:
-                                if pattern.regex.search(_content):
-                                    self._set_detected_app(webpage.url, tech_fingerprint, 'dom', pattern, value=_content)
-                                    has_tech = True
+            if is_valid_selector(selector.selector):
+                for item in webpage.select(selector.selector):
+                    if selector.exists:
+                        self._set_detected_app(webpage.url, tech_fingerprint, 'dom', Pattern(string=selector.selector), value='')
+                        has_tech = True
+                    if selector.text:
+                        for pattern in selector.text:
+                            if pattern.regex.search(item.inner_html):
+                                self._set_detected_app(webpage.url, tech_fingerprint, 'dom', pattern, value=item.inner_html)
+                                has_tech = True
+                    if selector.attributes:
+                        for attrname, patterns in list(selector.attributes.items()):
+                            _content = item.attributes.get(attrname)
+                            if _content:
+                                for pattern in patterns:
+                                    if pattern.regex.search(_content):
+                                        self._set_detected_app(webpage.url, tech_fingerprint, 'dom', pattern, value=_content)
+                                        has_tech = True
         return has_tech
 
     def _set_detected_app(self, url:str,
diff --git a/setup.py b/setup.py
index 9c8c46a..16fb7f6 100644
--- a/setup.py
+++ b/setup.py
@@ -3,7 +3,7 @@
 
 setup(
     name                =   "python-Wappalyzer",
-    version             =   "0.4.0",
+    version             =   "0.4.2",
     description         =   "Python implementation of the Wappalyzer web application "
                             "detection utility",
     long_description    =   (pathlib.Path(__file__).parent / "README.rst").read_text(),
@@ -31,4 +31,4 @@
                                      "types-requests", "types-pkg_resources", "aioresponses"]
                             },
     python_requires     =   '>=3.6',
-)
\ No newline at end of file
+)