diff --git a/lib/middleware/request_tracker.rb b/lib/middleware/request_tracker.rb
index 897a09a8fda..5f3a1f74583 100644
--- a/lib/middleware/request_tracker.rb
+++ b/lib/middleware/request_tracker.rb
@@ -117,7 +117,12 @@ class Middleware::RequestTracker
     }
 
     if h[:is_crawler]
-      h[:user_agent] = env['HTTP_USER_AGENT']
+      user_agent = env['HTTP_USER_AGENT']
+      if user_agent.encoding != Encoding::UTF_8
+        user_agent = user_agent.encode("utf-8")
+        user_agent.scrub!
+      end
+      h[:user_agent] = user_agent
     end
 
     if cache = headers["X-Discourse-Cached"]
diff --git a/spec/components/middleware/request_tracker_spec.rb b/spec/components/middleware/request_tracker_spec.rb
index 8faeaf079eb..d6c413cb9de 100644
--- a/spec/components/middleware/request_tracker_spec.rb
+++ b/spec/components/middleware/request_tracker_spec.rb
@@ -15,6 +15,26 @@ describe Middleware::RequestTracker do
     }.merge(opts)
   end
 
+  context "full request" do
+    before do
+      @orig = WebCrawlerRequest.autoflush
+      WebCrawlerRequest.autoflush = 1
+    end
+    after do
+      WebCrawlerRequest.autoflush = @orig
+    end
+
+    it "can handle rogue user agents" do
+      agent = (+"Evil Googlebot String \xc3\x28").force_encoding("Windows-1252")
+
+      middleware = Middleware::RequestTracker.new(->(env) { ["200", { "Content-Type" => "text/html" }, [""]] })
+      middleware.call(env("HTTP_USER_AGENT" => agent))
+
+      expect(WebCrawlerRequest.where(user_agent: agent.encode('utf-8')).count).to eq(1)
+    end
+
+  end
+
   context "log_request" do
     before do
       freeze_time Time.now