diff --git a/Appraisals b/Appraisals
index a5201bde..276a227a 100644
--- a/Appraisals
+++ b/Appraisals
@@ -10,7 +10,7 @@
 # > https://github.com/thoughtbot/appraisal
 
 appraise "ar-4.2" do
-  gem "activerecord", "~> 4.2.10"
+  gem "activerecord", [">= 4.2.11.1", "< 4.3"] # CVE-2019-5420
   gem "database_cleaner", "~> 1.6"
 
   # not compatible with mysql2 0.5
@@ -22,17 +22,16 @@ appraise "ar-4.2" do
 end
 
 appraise "ar-5.1" do
-  gem "activerecord", "~> 5.1.5"
+  gem "activerecord", [">= 5.1.6.2", "< 5.2"] # CVE-2019-5420
   gem "rails-controller-testing", "~> 1.0.2"
 end
 
 appraise "ar-5.2" do
-  gem "activerecord", "~> 5.2.1"
+  gem "activerecord", [">= 5.2.2.1", "< 5.3"] # CVE-2019-5420
   gem "rails-controller-testing", "~> 1.0.2"
 end
 
 appraise "ar-6.0" do
-  # TODO: Use actual version number once 6.0 final is released
-  gem "activerecord", "~> 6.0.0.beta1"
+  gem "activerecord", [">= 6.0.0.beta3", "< 6.1"] # CVE-2019-5420
   gem "rails-controller-testing", "~> 1.0.3"
 end
diff --git a/gemfiles/ar_4.2.gemfile b/gemfiles/ar_4.2.gemfile
index 8e00c9bd..d1c0e948 100644
--- a/gemfiles/ar_4.2.gemfile
+++ b/gemfiles/ar_4.2.gemfile
@@ -2,7 +2,7 @@
 
 source "https://rubygems.org"
 
-gem "activerecord", "~> 4.2.10"
+gem "activerecord", [">= 4.2.11.1", "< 4.3"]
 gem "database_cleaner", "~> 1.6"
 gem "mysql2", "~> 0.4.10"
 gem "pg", "~> 0.21.0"
diff --git a/gemfiles/ar_5.1.gemfile b/gemfiles/ar_5.1.gemfile
index 6f8e07d1..c822d943 100644
--- a/gemfiles/ar_5.1.gemfile
+++ b/gemfiles/ar_5.1.gemfile
@@ -2,7 +2,7 @@
 
 source "https://rubygems.org"
 
-gem "activerecord", "~> 5.1.5"
+gem "activerecord", [">= 5.1.6.2", "< 5.2"]
 gem "rails-controller-testing", "~> 1.0.2"
 
 gemspec path: "../"
diff --git a/gemfiles/ar_5.2.gemfile b/gemfiles/ar_5.2.gemfile
index cd895511..28238464 100644
--- a/gemfiles/ar_5.2.gemfile
+++ b/gemfiles/ar_5.2.gemfile
@@ -2,7 +2,7 @@
 
 source "https://rubygems.org"
 
-gem "activerecord", "~> 5.2.1"
+gem "activerecord", [">= 5.2.2.1", "< 5.3"]
 gem "rails-controller-testing", "~> 1.0.2"
 
 gemspec path: "../"
diff --git a/gemfiles/ar_6.0.gemfile b/gemfiles/ar_6.0.gemfile
index 92920504..63bb6cb2 100644
--- a/gemfiles/ar_6.0.gemfile
+++ b/gemfiles/ar_6.0.gemfile
@@ -2,7 +2,7 @@
 
 source "https://rubygems.org"
 
-gem "activerecord", "~> 6.0.0.beta1"
+gem "activerecord", [">= 6.0.0.beta3", "< 6.1"]
 gem "rails-controller-testing", "~> 1.0.3"
 
 gemspec path: "../"