diff --git a/changelogs/unreleased/sh-normalize-urls.yml b/changelogs/unreleased/sh-normalize-urls.yml
new file mode 100644
index 0000000000000000000000000000000000000000..b0d1120e10bc02c5a3796aff65efe47b8a7d5603
--- /dev/null
+++ b/changelogs/unreleased/sh-normalize-urls.yml
@@ -0,0 +1,5 @@
+---
+title: Escape username and password in UrlSanitizer#full_url
+merge_request: 20684
+author:
+type: fixed
diff --git a/lib/gitlab/url_sanitizer.rb b/lib/gitlab/url_sanitizer.rb
index de8b6ec69ce77d598b8f78be3f2512434bce51b6..308a95d2f09e3a9265a2218dd114607dfeecf7ff 100644
--- a/lib/gitlab/url_sanitizer.rb
+++ b/lib/gitlab/url_sanitizer.rb
@@ -71,12 +71,10 @@ module Gitlab
     def generate_full_url
       return @url unless valid_credentials?
 
-      @full_url = @url.dup
-
-      @full_url.password = credentials[:password] if credentials[:password].present?
-      @full_url.user = credentials[:user] if credentials[:user].present?
-
-      @full_url
+      @url.dup.tap do |generated|
+        generated.password = encode_percent(credentials[:password]) if credentials[:password].present?
+        generated.user = encode_percent(credentials[:user]) if credentials[:user].present?
+      end
     end
 
     def safe_url
@@ -89,5 +87,10 @@ module Gitlab
     def valid_credentials?
       credentials && credentials.is_a?(Hash) && credentials.any?
     end
+
+    def encode_percent(string)
+      # CGI.escape converts spaces to +, but this doesn't work for git clone
+      CGI.escape(string).gsub('+', '%20')
+    end
   end
 end
diff --git a/spec/lib/gitlab/url_sanitizer_spec.rb b/spec/lib/gitlab/url_sanitizer_spec.rb
index 758a9bc5a2b4b2138dbc8fbb684bfef4737c513f..b41a81a8167d893144408304227e462532692806 100644
--- a/spec/lib/gitlab/url_sanitizer_spec.rb
+++ b/spec/lib/gitlab/url_sanitizer_spec.rb
@@ -145,6 +145,10 @@ describe Gitlab::UrlSanitizer do
         'http://foo:@example.com'    | 'http://foo@example.com'
         'http://:bar@example.com'    | :same
         'http://foo:bar@example.com' | :same
+        'http://foo:g p@example.com' | 'http://foo:g%20p@example.com'
+        'http://foo:s/h@example.com' | 'http://foo:s%2Fh@example.com'
+        'http://t u:a#b@example.com' | 'http://t%20u:a%23b@example.com'
+        'http://t+u:a#b@example.com' | 'http://t%2Bu:a%23b@example.com'
       end
 
       with_them do
@@ -160,7 +164,7 @@ describe Gitlab::UrlSanitizer do
       url_sanitizer = described_class.new("https://foo:b?r@github.com/me/project.git")
 
       expect(url_sanitizer.sanitized_url).to eq("https://github.com/me/project.git")
-      expect(url_sanitizer.full_url).to eq("https://foo:b?r@github.com/me/project.git")
+      expect(url_sanitizer.full_url).to eq("https://foo:b%3Fr@github.com/me/project.git")
     end
   end
 end