diff --git a/pkgs/applications/networking/mailreaders/neomutt/default.nix b/pkgs/applications/networking/mailreaders/neomutt/default.nix
index 2126d00d6128..610003ec96b8 100644
--- a/pkgs/applications/networking/mailreaders/neomutt/default.nix
+++ b/pkgs/applications/networking/mailreaders/neomutt/default.nix
@@ -42,6 +42,10 @@ in stdenv.mkDerivation rec {
         --replace http://docbook.sourceforge.net/release/xsl/current     ${docbook_xsl}/share/xml/docbook-xsl \
         --replace http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd ${docbook_xml_dtd_42}/xml/dtd/docbook/docbookx.dtd
     done
+
+    # allow neomutt to map attachments to their proper mime.types if specified wrongly
+    substituteInPlace sendlib.c \
+      --replace /etc/mime.types $out/share/doc/neomutt/mime.types
   '';
 
   configureFlags = [