diff --git a/pkgs/development/libraries/nspr/default.nix b/pkgs/development/libraries/nspr/default.nix
index 9ab89aaefbfe..8a16803fd8bf 100644
--- a/pkgs/development/libraries/nspr/default.nix
+++ b/pkgs/development/libraries/nspr/default.nix
@@ -2,7 +2,7 @@
 , CoreServices ? null
 , buildPackages }:
 
-let version = "4.26"; in
+let version = "4.27"; in
 
 stdenv.mkDerivation {
   pname = "nspr";
@@ -10,7 +10,7 @@ stdenv.mkDerivation {
 
   src = fetchurl {
     url = "mirror://mozilla/nspr/releases/v${version}/src/nspr-${version}.tar.gz";
-    sha256 = "0gbp3g9p4nhf0zrlvqi5883sqb9zdw0wk83lccpgskxphlni97gw";
+    sha256 = "16z82qc1l4cqn66p59ai0dy9ycllywn4jlxhip1a605bns952jbd";
   };
 
   patches = [
diff --git a/pkgs/development/libraries/nss/default.nix b/pkgs/development/libraries/nss/default.nix
index ab1f05044708..3ede78aa015a 100644
--- a/pkgs/development/libraries/nss/default.nix
+++ b/pkgs/development/libraries/nss/default.nix
@@ -5,7 +5,7 @@ let
     url = "http://dev.gentoo.org/~polynomial-c/mozilla/nss-3.15.4-pem-support-20140109.patch.xz";
     sha256 = "10ibz6y0hknac15zr6dw4gv9nb5r5z9ym6gq18j3xqx7v7n3vpdw";
   };
-  version = "3.54";
+  version = "3.55";
   underscoreVersion = builtins.replaceStrings ["."] ["_"] version;
 
 in stdenv.mkDerivation rec {
@@ -14,7 +14,7 @@ in stdenv.mkDerivation rec {
 
   src = fetchurl {
     url = "mirror://mozilla/security/nss/releases/NSS_${underscoreVersion}_RTM/src/${pname}-${version}.tar.gz";
-    sha256 = "0hvfip056pl07h6w91i6fyji5nczrrsxyr56rls7jd2yryzqpcfs";
+    sha256 = "0100hm7n1xrp144xy665z46s0wf1jpkqkncc6bk2w22snhyjwsgw";
   };
 
   depsBuildBuild = [ buildPackages.stdenv.cc ];