diff --git a/Makefile.PL b/Makefile.PL
index e34a44e40..8b3932e63 100644
--- a/Makefile.PL
+++ b/Makefile.PL
@@ -75,9 +75,11 @@ WriteMakefile(NAME => 'LaTeXML',
     'URI'               => 0,
     'version'           => 0,
     # Windows terminal handling (see Common::Error)
+    # Windows argument escaping (see Util::Pathname)
     ($^O eq 'MSWin32'
       ? ('Win32::Console' => 0,
-        'Win32::Console::ANSI' => 0)
+        'Win32::Console::ANSI' => 0,
+        'Win32::ShellQuote'    => 0)
       : ()),
     # If we have an "old" version of XML::LibXML,
     # we also need XPathContext.
diff --git a/lib/LaTeXML/Package.pm b/lib/LaTeXML/Package.pm
index 4b18d62a9..f51100d65 100644
--- a/lib/LaTeXML/Package.pm
+++ b/lib/LaTeXML/Package.pm
@@ -2016,8 +2016,6 @@ sub FindFile_aux {
       return $file . '.ltxml' if -f ($file . '.ltxml'); }    # No need to search, just check if it exists.
     return $file if -f $file;    # No need to search, just check if it exists.
     return; }                    # otherwise we're never going to find it.
-  elsif (pathname_is_nasty($file)) {    # If it is a nasty filename, we won't touch it.
-    return; }                           # we DO NOT want to pass this to kpathse or such!
 
   # Note that the strategy is complicated by the fact that
   # (1) we prefer .ltxml bindings, if present
@@ -2026,7 +2024,7 @@ sub FindFile_aux {
   # (4) depending on switches we may EXCLUDE .ltxml OR raw tex OR allow both.
   # (5) we may allow interpreting raw TeX/sty/whatever files individually or broadly
   # (6) but we may also want to override an apparently "versioned" file, preferring the ltxml
-  my $paths         = LookupValue('SEARCHPATHS');
+  my $paths         = LookupValue('SEARCHPATHS') // [];
   my $urlbase       = LookupValue('URLBASE');
   my $nopaths       = LookupValue('REMOTE_REQUEST');
   my $ltxml_paths   = $nopaths ? [] : $paths;
@@ -2053,8 +2051,7 @@ sub FindFile_aux {
   # Otherwise, pass on to kpsewhich
   # Depending on flags, maybe search for ltxml in texmf or for plain tex in ours!
   # The main point, though, is to we make only ONE (more) call.
-  return if grep { pathname_is_nasty($_) } @$paths;    # SECURITY! No nasty paths in cmdline
-      # Do we need to sanitize these environment variables?
+  # Do we need to sanitize these environment variables?
   my @candidates = (((!$options{noltxml} && !$nopaths) ? ("$file.ltxml") : ()),
     (!$options{notex} ? ($file) : ()));
   local $ENV{TEXINPUTS} = join($Config::Config{'path_sep'},
@@ -2138,10 +2135,6 @@ sub FindFile_fallback {
   else {
     return; } }
 
-sub pathname_is_nasty {
-  my ($pathname) = @_;
-  return $pathname =~ /[^\w\-_\+\=\/\\\.~\:\s]/; }
-
 sub maybeReportSearchPaths {
   if (LookupValue('SEARCHPATHS_REPORTED')) {
     return (); }
diff --git a/lib/LaTeXML/Util/Pathname.pm b/lib/LaTeXML/Util/Pathname.pm
index 829df9606..9407c65fe 100644
--- a/lib/LaTeXML/Util/Pathname.pm
+++ b/lib/LaTeXML/Util/Pathname.pm
@@ -46,6 +46,13 @@ our @EXPORT = qw( &pathname_find &pathname_findall &pathname_kpsewhich
   &pathname_cwd &pathname_chdir &pathname_mkdir &pathname_copy
   &pathname_installation);
 
+my $ISWINDOWS;
+
+BEGIN {
+  $ISWINDOWS = $^O =~ /^(MSWin|NetWare|cygwin)/i;
+  require Win32::ShellQuote if $ISWINDOWS;
+}
+
 # NOTE: For absolute pathnames, the directory component starts with
 # whatever File::Spec considers to be the volume, or "/".
 #======================================================================
@@ -54,7 +61,6 @@ our @EXPORT = qw( &pathname_find &pathname_findall &pathname_kpsewhich
 ### my $SEP         = '/';                          # [CONSTANT]
 # Some indicators that this is not sufficient? (calls to libraries/externals???)
 # PRELIMINARY test, probably need to be even more careful
-my $ISWINDOWS   = $^O =~ /^(MSWin|NetWare|cygwin)/i;
 my $SEP         = ($ISWINDOWS ? '\\' : '/');    # [CONSTANT]
 my $KPATHSEP    = ($ISWINDOWS ? ';'  : ':');    # [CONSTANT]
 my $LITERAL_RE  = '(?:literal)(?=:)';           # [CONSTANT]
@@ -391,6 +397,8 @@ our $kpse_toolchain = "";
 
 sub pathname_kpsewhich {
   my (@candidates) = @_;
+  # ($kpsewhich,@candidates) MUST NOT be empty to guarantee that Perl runs $kpsewhich directly
+  # rather than through a shell or cmd.exe
   return             unless $kpsewhich && @candidates;
   build_kpse_cache() unless $kpse_cache;
   foreach my $file (@candidates) {
@@ -400,7 +408,10 @@ sub pathname_kpsewhich {
   # For multiple calls, this is slower in general. But MiKTeX, eg., doesn't use texmf ls-R files!
   if ($kpse_toolchain) {
     push(@candidates, $kpse_toolchain); }
-  if ($kpsewhich && open(my $resfh, '-|', $kpsewhich, @candidates)) {
+  if ($kpsewhich && open(my $resfh, '-|',
+      # on Windows, ($kpsewhich, @candidates) is joined into a single string, which most binaries
+      # parse with CommandLineToArgvW, so the arguments must be escaped accordingly
+      $ISWINDOWS ? Win32::ShellQuote::quote_system_list($kpsewhich, @candidates) : ($kpsewhich, @candidates))) {
     my $result = <$resfh>;     # we only need the first line
     { local $/; <$resfh>; }    # discard the rest of the output
     close($resfh);             # ignore exit status (only one of @candidates exists, usually)