diff --git a/Library/Homebrew/cmd/tap.rb b/Library/Homebrew/cmd/tap.rb
index d13921572f..3fb5ca65c4 100644
--- a/Library/Homebrew/cmd/tap.rb
+++ b/Library/Homebrew/cmd/tap.rb
@@ -123,7 +123,7 @@ module Homebrew
     case path.to_s
     when HOMEBREW_TAP_PATH_REGEX
       "#$1/#$2/#{File.basename($3, '.rb')}"
-    when %r{^#{HOMEBREW_LIBRARY}/Formula/(.+)}
+    when %r{^#{Regexp.escape(HOMEBREW_LIBRARY.to_s)}/Formula/(.+)}o
       "Homebrew/homebrew/#{File.basename($1, '.rb')}"
     else
       nil
diff --git a/Library/Homebrew/cmd/update.rb b/Library/Homebrew/cmd/update.rb
index 7bced13a98..b1ee8d8fef 100644
--- a/Library/Homebrew/cmd/update.rb
+++ b/Library/Homebrew/cmd/update.rb
@@ -266,7 +266,7 @@ class Report
   def select_formula key
     fetch(key, []).map do |path|
       case path.to_s
-      when Regexp.new(HOMEBREW_LIBRARY + "/Formula")
+      when %r{^#{Regexp.escape(HOMEBREW_LIBRARY.to_s)}/Formula}o
         path.basename(".rb").to_s
       when HOMEBREW_TAP_PATH_REGEX
         "#$1/#{$2.sub("homebrew-", "")}/#{path.basename(".rb")}"
diff --git a/Library/Homebrew/tap_constants.rb b/Library/Homebrew/tap_constants.rb
index d706d85296..3550a06377 100644
--- a/Library/Homebrew/tap_constants.rb
+++ b/Library/Homebrew/tap_constants.rb
@@ -3,6 +3,6 @@ HOMEBREW_TAP_ARGS_REGEX = %r{^([\w-]+)/(homebrew-)?([\w-]+)$}
 # match taps' formula, e.g. someuser/sometap/someformula
 HOMEBREW_TAP_FORMULA_REGEX = %r{^([\w-]+)/([\w-]+)/([\w+-]+)$}
 # match taps' directory path, e.g. HOMEBREW_LIBRARY/Taps/someuser/sometap
-HOMEBREW_TAP_DIR_REGEX = %r{#{HOMEBREW_LIBRARY}/Taps/([\w-]+)/([\w-]+)}
+HOMEBREW_TAP_DIR_REGEX = %r{#{Regexp.escape(HOMEBREW_LIBRARY.to_s)}/Taps/([\w-]+)/([\w-]+)}
 # match taps' formula path, e.g. HOMEBREW_LIBRARY/Taps/someuser/sometap/someformula
 HOMEBREW_TAP_PATH_REGEX = Regexp.new(HOMEBREW_TAP_DIR_REGEX.source + %r{/(.*)}.source)