diff --git a/pkgs/development/libraries/haskell/yesod-core/default.nix b/pkgs/development/libraries/haskell/yesod-core/default.nix
index 96995f24d31..89f09602410 100644
--- a/pkgs/development/libraries/haskell/yesod-core/default.nix
+++ b/pkgs/development/libraries/haskell/yesod-core/default.nix
@@ -13,8 +13,8 @@
 
 cabal.mkDerivation (self: {
   pname = "yesod-core";
-  version = "1.2.17";
-  sha256 = "199zj9yz5nmk4h2dwz4zlix3wf1z5fl9a8jg8cr4z6ldgskcfis1";
+  version = "1.2.18";
+  sha256 = "08d62wjx8smvi75490fp2f5ayv5jsgkxqi33lqhv9lxgv3ckk8vi";
   buildDepends = [
     aeson attoparsecConduit blazeBuilder blazeHtml blazeMarkup
     caseInsensitive cereal clientsession conduit conduitExtra cookie