diff --git a/yt_dlp/extractor/cbc.py b/yt_dlp/extractor/cbc.py
index be2d13e44..29f0e307d 100644
--- a/yt_dlp/extractor/cbc.py
+++ b/yt_dlp/extractor/cbc.py
@@ -1,8 +1,9 @@
-import re
-import json
 import base64
+import json
+import re
 import time
 import urllib.parse
+import xml.etree.ElementTree
 
 from .common import InfoExtractor
 from ..compat import (
@@ -387,7 +388,7 @@ def _find_secret_formats(self, formats, video_id):
         url = re.sub(r'(Manifest\(.*?),format=[\w-]+(.*?\))', r'\1\2', base_url)
 
         secret_xml = self._download_xml(url, video_id, note='Downloading secret XML', fatal=False)
-        if not secret_xml:
+        if not isinstance(secret_xml, xml.etree.ElementTree.Element):
             return
 
         for child in secret_xml:
diff --git a/yt_dlp/extractor/common.py b/yt_dlp/extractor/common.py
index c3ceb0039..b3a45b3fb 100644
--- a/yt_dlp/extractor/common.py
+++ b/yt_dlp/extractor/common.py
@@ -2225,7 +2225,9 @@ def _extract_mpd_vod_duration(
             mpd_url, video_id,
             note='Downloading MPD VOD manifest' if note is None else note,
             errnote='Failed to download VOD manifest' if errnote is None else errnote,
-            fatal=False, data=data, headers=headers, query=query) or {}
+            fatal=False, data=data, headers=headers, query=query)
+        if not isinstance(mpd_doc, xml.etree.ElementTree.Element):
+            return None
         return int_or_none(parse_duration(mpd_doc.get('mediaPresentationDuration')))
 
     @staticmethod
diff --git a/yt_dlp/extractor/mtv.py b/yt_dlp/extractor/mtv.py
index 0d700b9a8..e192453c7 100644
--- a/yt_dlp/extractor/mtv.py
+++ b/yt_dlp/extractor/mtv.py
@@ -1,4 +1,5 @@
 import re
+import xml.etree.ElementTree
 
 from .common import InfoExtractor
 from ..compat import compat_str
@@ -137,7 +138,7 @@ def _get_video_info(self, itemdoc, use_hls=True):
         mediagen_doc = self._download_xml(
             mediagen_url, video_id, 'Downloading video urls', fatal=False)
 
-        if mediagen_doc is False:
+        if not isinstance(mediagen_doc, xml.etree.ElementTree.Element):
             return None
 
         item = mediagen_doc.find('./video/item')
diff --git a/yt_dlp/extractor/nbc.py b/yt_dlp/extractor/nbc.py
index 666550a49..2d3aa26ec 100644
--- a/yt_dlp/extractor/nbc.py
+++ b/yt_dlp/extractor/nbc.py
@@ -1,6 +1,7 @@
 import base64
 import json
 import re
+import xml.etree.ElementTree
 
 from .common import InfoExtractor
 from .theplatform import ThePlatformIE, default_ns
@@ -803,8 +804,10 @@ def _real_extract(self, url):
             smil = self._download_xml(
                 f'https://link.theplatform.com/s/{pdk_acct}/{player_id}', video_id,
                 note='Downloading SMIL data', query=query, fatal=is_live)
-        subtitles = self._parse_smil_subtitles(smil, default_ns) if smil else {}
-        for video in smil.findall(self._xpath_ns('.//video', default_ns)) if smil else []:
+            if not isinstance(smil, xml.etree.ElementTree.Element):
+                smil = None
+        subtitles = self._parse_smil_subtitles(smil, default_ns) if smil is not None else {}
+        for video in smil.findall(self._xpath_ns('.//video', default_ns)) if smil is not None else []:
             info['duration'] = float_or_none(remove_end(video.get('dur'), 'ms'), 1000)
             video_src_url = video.get('src')
             ext = mimetype2ext(video.get('type'), default=determine_ext(video_src_url))
diff --git a/yt_dlp/extractor/slideslive.py b/yt_dlp/extractor/slideslive.py
index 25f867a60..13f3109d7 100644
--- a/yt_dlp/extractor/slideslive.py
+++ b/yt_dlp/extractor/slideslive.py
@@ -1,5 +1,6 @@
 import re
 import urllib.parse
+import xml.etree.ElementTree
 
 from .common import InfoExtractor
 from ..utils import (
@@ -469,11 +470,12 @@ def _real_extract(self, url):
             slides = self._download_xml(
                 player_info['slides_xml_url'], video_id, fatal=False,
                 note='Downloading slides XML', errnote='Failed to download slides info')
-            slide_url_template = 'https://cdn.slideslive.com/data/presentations/%s/slides/big/%s%s'
-            for slide_id, slide in enumerate(slides.findall('./slide') if slides else [], 1):
-                slides_info.append((
-                    slide_id, xpath_text(slide, './slideName', 'name'), '.jpg',
-                    int_or_none(xpath_text(slide, './timeSec', 'time'))))
+            if isinstance(slides, xml.etree.ElementTree.Element):
+                slide_url_template = 'https://cdn.slideslive.com/data/presentations/%s/slides/big/%s%s'
+                for slide_id, slide in enumerate(slides.findall('./slide')):
+                    slides_info.append((
+                        slide_id, xpath_text(slide, './slideName', 'name'), '.jpg',
+                        int_or_none(xpath_text(slide, './timeSec', 'time'))))
 
         chapters, thumbnails = [], []
         if url_or_none(player_info.get('thumbnail')):