diff --git a/Gemfile b/Gemfile
index 3ab3989cf9a..4558a8a5f59 100644
--- a/Gemfile
+++ b/Gemfile
@@ -44,7 +44,7 @@ end
 
 group :build do
   gem 'kramdown'
-  gem 'mustache'
+  gem 'mustache', '< 1.1.3'
 end
 
 group :development do
diff --git a/build_tools/aws-sdk-code-generator/aws-sdk-code-generator.gemspec b/build_tools/aws-sdk-code-generator/aws-sdk-code-generator.gemspec
index 32b108d822a..4fd8ad6de64 100644
--- a/build_tools/aws-sdk-code-generator/aws-sdk-code-generator.gemspec
+++ b/build_tools/aws-sdk-code-generator/aws-sdk-code-generator.gemspec
@@ -13,5 +13,5 @@ Gem::Specification.new do |spec|
   spec.files = Dir['lib/**/*.rb'] + Dir['templates/**/*.mustache', 'templates/license.txt']
 
   spec.add_dependency('kramdown')
-  spec.add_dependency('mustache')
+  spec.add_dependency('mustache', '< 1.1.3')
 end