diff --git a/git-cvsserver.perl b/git-cvsserver.perl
index cbcaeb44e4..fef7faf339 100755
--- a/git-cvsserver.perl
+++ b/git-cvsserver.perl
@@ -2533,12 +2533,18 @@ sub open_blob_or_die
     return $fh;
 }
 
-# Generate a CVS author name from Git author information, by taking
-# the first eight characters of the user part of the email address.
+# Generate a CVS author name from Git author information, by taking the local
+# part of the email address and replacing characters not in the Portable
+# Filename Character Set (see IEEE Std 1003.1-2001, 3.276) by underscores. CVS
+# Login names are Unix login names, which should be restricted to this
+# character set.
 sub cvs_author
 {
     my $author_line = shift;
-    (my $author) = $author_line =~ /<([^>@]{1,8})/;
+    (my $author) = $author_line =~ /<([^@>]*)/;
+
+    $author =~ s/[^-a-zA-Z0-9_.]/_/g;
+    $author =~ s/^-/_/;
 
     $author;
 }