diff --git a/qgis-app/plugins/tests/test_validator.py b/qgis-app/plugins/tests/test_validator.py
index bfde21af..641870e9 100644
--- a/qgis-app/plugins/tests/test_validator.py
+++ b/qgis-app/plugins/tests/test_validator.py
@@ -18,8 +18,10 @@ def setUp(self):
         )
         web_not_exist_plugins = os.path.join(TESTFILE_DIR, "web_not_exist.zip")
         valid_plugins = os.path.join(TESTFILE_DIR, "valid_metadata_link.zip")
+        invalid_metadata_multiline = os.path.join(TESTFILE_DIR, "invalid_metadata_multiline.zip_")
         self.valid_metadata_link = open(valid_plugins, "rb")
         self.invalid_metadata_link = open(invalid_plugins, "rb")
+        self.invalid_metadata_multiline = open(invalid_metadata_multiline, "rb")
         self.web_not_exist = open(web_not_exist_plugins, "rb")
         self.invalid_url_scheme = open(invalid_url_scheme_plugins, "rb")
 
@@ -66,6 +68,27 @@ def test_invalid_metadata_link_tracker_repo_homepage(self):
             ),
         )
 
+    def test_invalid_metadata_multiline_attribute(self):
+        """
+        The invalid_metadata_multiline.zip contains metadata file with
+        a multiline attribute that is commented but still has value.
+        The parser will append the value of the attribute to the previous 
+        one and make it invalid.
+        """
+
+        self.assertRaises(
+            ValidationError,
+            validator,
+            InMemoryUploadedFile(
+                self.invalid_metadata_multiline,
+                field_name="tempfile",
+                name="testfile.zip",
+                content_type="application/zip",
+                size=39889,
+                charset="utf8",
+            ),
+        )
+
     def test_invalid_metadata_url_scheme(self):
         """
         The invalid_url_scheme.zip contains metadata file with
diff --git a/qgis-app/plugins/tests/testfiles/invalid_metadata_multiline.zip_ b/qgis-app/plugins/tests/testfiles/invalid_metadata_multiline.zip_
new file mode 100644
index 00000000..afcd4fb5
Binary files /dev/null and b/qgis-app/plugins/tests/testfiles/invalid_metadata_multiline.zip_ differ
diff --git a/qgis-app/plugins/validator.py b/qgis-app/plugins/validator.py
index e75d9755..ebb3a34c 100644
--- a/qgis-app/plugins/validator.py
+++ b/qgis-app/plugins/validator.py
@@ -96,6 +96,28 @@ def _check_required_metadata(metadata):
             )
         )
 
+def _check_multiline_metadata(metadata):
+    """
+    Only the fields 'description', 'about' and 'changelog' can be multiline
+    If other fields are multiline, raise ValidationError
+    """
+    allowed_multiline_fields = ['description', 'about', 'changelog']
+    multiline_fields = [
+        field for field in [item[0] for item in metadata]
+        if field not in ['description', 'about', 'changelog'] and '\n' in dict(metadata).get(field, '')
+    ]
+    if len(multiline_fields) > 0:
+        multiline_fields_str = ', '.join(multiline_fields)
+        allowed_multiline_fields_str = ', '.join(allowed_multiline_fields)
+        raise ValidationError(
+            _(
+            f'The following metadata fields must be single-line: <code>{multiline_fields_str}</code>. '
+            'Please ensure these fields contain single-line values only. Note that multiline values can also occur if an allowed '
+            f'multiline field (<code>{allowed_multiline_fields_str}</code>) is commented out but still contains a multiline value.'
+            )
+        )
+
+
 def _check_url_link(urls):
     """
     Checks if all the url link is valid.
@@ -293,6 +315,7 @@ def validator(package, is_new: bool = False):
         metadata.append(("metadata_source", "__init__.py"))
 
     _check_required_metadata(metadata)
+    _check_multiline_metadata(metadata)
 
     # Process Icon
     try:
@@ -375,7 +398,6 @@ def validator(package, is_new: bool = False):
     if "author" in dict(metadata):
         if not re.match(r"^[^/]+$", dict(metadata)["author"]):
             raise ValidationError(_("Author name cannot contain slashes."))
-
     # strip and check
     checked_metadata = []
     for k, v in metadata: