diff --git a/pkgs/applications/networking/mailreaders/sylpheed/default.nix b/pkgs/applications/networking/mailreaders/sylpheed/default.nix
index 9a65bec21c20..32350bb5cfa7 100644
--- a/pkgs/applications/networking/mailreaders/sylpheed/default.nix
+++ b/pkgs/applications/networking/mailreaders/sylpheed/default.nix
@@ -19,13 +19,17 @@ stdenv.mkDerivation rec {
     (fetchpatch {
       # patch upstream bug https://sylpheed.sraoss.jp/redmine/issues/306
       name = "patch-libsylph_ssl_c.patch";
+      extraPrefix = "";
       url = "https://cvsweb.openbsd.org/cgi-bin/cvsweb/~checkout~/ports/mail/sylpheed/patches/patch-libsylph_ssl_c?rev=1.4&content-type=text/plain";
-      sha256 = "sha256-k9OwPtHrEjaxXdH0trNqXgJMhR8kjgtei9pi6OFvILk=";
+      sha256 = "sha256-+FetU5vrfvE78nYAjKK/QFZnFw+Zr2PvoUGRWCuZczs=";
+    })
+    (fetchpatch {
+      name = "CVE-2021-37746.patch";
+      url = "https://git.claws-mail.org/?p=claws.git;a=patch;h=ac286a71ed78429e16c612161251b9ea90ccd431";
+      sha256 = "sha256-oLmUShtvO6io3jibKT67eO0O58vEDZEeaB51QTd3UkU=";
     })
   ];
 
-  patchFlags = [ "-p0" ];
-
   nativeBuildInputs = [ pkg-config ];
 
   buildInputs = [ gtk2 ]