diff --git a/pkgs/shells/ksh/default.nix b/pkgs/shells/ksh/default.nix
index ae9dba16aedf..0751ef64dbb0 100644
--- a/pkgs/shells/ksh/default.nix
+++ b/pkgs/shells/ksh/default.nix
@@ -17,8 +17,8 @@ stdenv.mkDerivation (finalAttrs: {
   src = fetchFromGitHub {
     owner = "att";
     repo = "ast";
-    rev = finalAttrs.version;
     sha256 = "0cdxz0nhpq03gb9rd76fn0x1yzs2c8q289b7vcxnzlsrz1imz65j";
+    rev = "refs/tags/${finalAttrs.version}";
   };
 
   patches = [