diff --git a/etc/nginx.conf b/etc/nginx.conf
index 95a109aaf4..f946635b7c 100644
--- a/etc/nginx.conf
+++ b/etc/nginx.conf
@@ -83,6 +83,9 @@ http {
         server_name  _;
 
         location /uploads/  {
+            # prevent browser from possibly interpreting untrusted files
+            add_header Content-Type "text/plain";
+
             alias /Kiwi/uploads/;
         }
 
diff --git a/tcms/core/middleware.py b/tcms/core/middleware.py
index 1f0e608dc1..e54a7ddc67 100644
--- a/tcms/core/middleware.py
+++ b/tcms/core/middleware.py
@@ -34,4 +34,7 @@ def process_response(self, request, response):
                 "Content-Security-Policy"
             ] = "script-src 'self' cdn.crowdin.com;"
 
+            if request.path.find("/uploads/") > -1:
+                response.headers["Content-Type"] = "text/plain"
+
         return response
diff --git a/tests/test_http.sh b/tests/test_http.sh
index 4f2ce85ef6..df624643a0 100755
--- a/tests/test_http.sh
+++ b/tests/test_http.sh
@@ -97,8 +97,13 @@ _EOF_
             # copy test file externally b/c Kiwi TCMS v12.2 will prevent its upload
             rlRun -t -c "docker exec -i kiwi_web /bin/bash -c 'mkdir -p /Kiwi/uploads/attachments/auth_user/2/'"
             rlRun -t -c "docker cp tests/ui/data/inline_javascript.svg kiwi_web:/Kiwi/uploads/attachments/auth_user/2/"
+            rlRun -t -c "curl -k -D- https://localhost/uploads/attachments/auth_user/2/inline_javascript.svg 2>/dev/null | grep 'Content-Type: text/plain'"
+
+            rlRun -t -c "docker cp tests/ui/data/redirect.js kiwi_web:/Kiwi/uploads/attachments/auth_user/2/"
+            rlRun -t -c "docker cp tests/ui/data/html_with_external_script.html kiwi_web:/Kiwi/uploads/attachments/auth_user/2/"
+            rlRun -t -c "curl -k -D- https://localhost/uploads/attachments/auth_user/2/redirect.js 2>/dev/null | grep 'Content-Type: text/plain'"
+            rlRun -t -c "curl -k -D- https://localhost/uploads/attachments/auth_user/2/html_with_external_script.html 2>/dev/null | grep 'Content-Type: text/plain'"
 
-            rlRun -t -c "curl -k --fail https://localhost/uploads/attachments/auth_user/2/inline_javascript.svg"
             rlRun -t -c "robot tests/ui/test_inline_javascript.robot"
         fi
     rlPhaseEnd
diff --git a/tests/ui/data/html_with_external_script.html b/tests/ui/data/html_with_external_script.html
new file mode 100644
index 0000000000..ea5c320df4
--- /dev/null
+++ b/tests/ui/data/html_with_external_script.html
@@ -0,0 +1 @@
+<script src="/uploads/attachments/auth_user/2/redirect.js"></script>
diff --git a/tests/ui/data/redirect.js b/tests/ui/data/redirect.js
new file mode 100644
index 0000000000..0a55d88ff6
--- /dev/null
+++ b/tests/ui/data/redirect.js
@@ -0,0 +1 @@
+location.replace('https://kiwitcms.org');
diff --git a/tests/ui/test_inline_javascript.robot b/tests/ui/test_inline_javascript.robot
index 15372b6e43..3f5b52f40e 100644
--- a/tests/ui/test_inline_javascript.robot
+++ b/tests/ui/test_inline_javascript.robot
@@ -6,6 +6,7 @@ ${SERVER}               https://localhost
 ${BROWSER}              Headless Firefox
 ${DELAY}                0
 ${SVG_URL}              ${SERVER}/uploads/attachments/auth_user/2/inline_javascript.svg
+${HTML_URL}             ${SERVER}/uploads/attachments/auth_user/2/html_with_external_script.html
 
 
 *** Test Cases ***
@@ -17,3 +18,13 @@ Directly accessing an SVG image should not execute inline JavaScript
     Location Should Be    ${SVG_URL}
 
     [Teardown]    Close Browser
+
+
+Directly accessing an HTML file should not execute JavaScript
+    Open Browser    ${HTML_URL}    ${BROWSER}
+    Maximize Browser Window
+    Set Selenium Speed    ${DELAY}
+
+    Location Should Be    ${HTML_URL}
+
+    [Teardown]    Close Browser