diff --git a/system/HTTP/ContentSecurityPolicy.php b/system/HTTP/ContentSecurityPolicy.php
index 04d93365af25..203e867372da 100644
--- a/system/HTTP/ContentSecurityPolicy.php
+++ b/system/HTTP/ContentSecurityPolicy.php
@@ -1052,4 +1052,9 @@ public function clearDirective(string $directive): void
 
         $this->{$this->directives[$directive]} = [];
     }
+
+    public function clearNoncePlaceholders(string $text): string
+    {
+        return str_replace([$this->styleNonceTag, $this->scriptNonceTag], '', $text);
+    }
 }
diff --git a/system/HTTP/ResponseTrait.php b/system/HTTP/ResponseTrait.php
index 211663bc7987..74b9e10c530d 100644
--- a/system/HTTP/ResponseTrait.php
+++ b/system/HTTP/ResponseTrait.php
@@ -370,7 +370,7 @@ public function send()
         if ($this->CSP->enabled()) {
             $this->CSP->finalize($this);
         } else {
-            $this->body = str_replace(['{csp-style-nonce}', '{csp-script-nonce}'], '', $this->body ?? '');
+            $this->body = $this->CSP->clearNoncePlaceholders($this->body);
         }
 
         $this->sendHeaders();
diff --git a/tests/system/HTTP/ContentSecurityPolicyTest.php b/tests/system/HTTP/ContentSecurityPolicyTest.php
index af9638b6a8ba..6e3c320c1eaf 100644
--- a/tests/system/HTTP/ContentSecurityPolicyTest.php
+++ b/tests/system/HTTP/ContentSecurityPolicyTest.php
@@ -937,4 +937,67 @@ public function testClearDirective(): void
         $this->assertNotContains('report-uri http://example.com/csp/reports', $directives);
         $this->assertNotContains('report-to default', $directives);
     }
+
+    public function testClearNoncePlaceholdersWithDefaultTags(): void
+    {
+        $config = new CSPConfig();
+        $csp    = new ContentSecurityPolicy($config);
+
+        $body = 'Test {csp-script-nonce} and {csp-style-nonce} here';
+        $cleaned = $csp->clearNoncePlaceholders($body);
+
+        $this->assertSame('Test  and  here', $cleaned);
+        $this->assertStringNotContainsString('{csp-script-nonce}', $cleaned);
+        $this->assertStringNotContainsString('{csp-style-nonce}', $cleaned);
+    }
+
+    public function testClearNoncePlaceholdersWithCustomTags(): void
+    {
+        $config                 = new CSPConfig();
+        $config->scriptNonceTag = '{custom-script-nonce}';
+        $config->styleNonceTag  = '{custom-style-nonce}';
+        $csp                    = new ContentSecurityPolicy($config);
+
+        $body = 'Test {custom-script-nonce} and {custom-style-nonce} here';
+        $cleaned = $csp->clearNoncePlaceholders($body);
+
+        $this->assertSame('Test  and  here', $cleaned);
+        $this->assertStringNotContainsString('{custom-script-nonce}', $cleaned);
+        $this->assertStringNotContainsString('{custom-style-nonce}', $cleaned);
+    }
+
+    public function testClearNoncePlaceholdersWithEmptyBody(): void
+    {
+        $config = new CSPConfig();
+        $csp    = new ContentSecurityPolicy($config);
+
+        $body = '';
+        $cleaned = $csp->clearNoncePlaceholders($body);
+
+        $this->assertSame('', $cleaned);
+    }
+
+    public function testClearNoncePlaceholdersWithNoPlaceholders(): void
+    {
+        $config = new CSPConfig();
+        $csp    = new ContentSecurityPolicy($config);
+
+        $body = 'Test body with no placeholders';
+        $cleaned = $csp->clearNoncePlaceholders($body);
+
+        $this->assertSame($body, $cleaned);
+    }
+
+    public function testClearNoncePlaceholdersWithMultiplePlaceholders(): void
+    {
+        $config = new CSPConfig();
+        $csp    = new ContentSecurityPolicy($config);
+
+        $body = '<script {csp-script-nonce}>a</script><script {csp-script-nonce}>b</script><style {csp-style-nonce}>c</style>';
+        $cleaned = $csp->clearNoncePlaceholders($body);
+
+        $this->assertStringNotContainsString('{csp-script-nonce}', $cleaned);
+        $this->assertStringNotContainsString('{csp-style-nonce}', $cleaned);
+        $this->assertSame('<script >a</script><script >b</script><style >c</style>', $cleaned);
+    }
 }
diff --git a/tests/system/HTTP/ResponseTest.php b/tests/system/HTTP/ResponseTest.php
index 84408df0e5a5..9ee3612da492 100644
--- a/tests/system/HTTP/ResponseTest.php
+++ b/tests/system/HTTP/ResponseTest.php
@@ -577,4 +577,80 @@ public function testPretendOutput(): void
 
         $this->assertSame('Happy days', $actual);
     }
+
+    public function testSendRemovesDefaultNoncePlaceholdersWhenCSPDisabled(): void
+    {
+        $config             = new App();
+        $config->CSPEnabled = false;
+
+        $response = new Response($config);
+        $response->pretend(true);
+
+        $body = '<html><script {csp-script-nonce}>console.log("test")</script><style {csp-style-nonce}>.test{}</style></html>';
+        $response->setBody($body);
+
+        ob_start();
+        $response->send();
+        $actual = ob_get_contents();
+        ob_end_clean();
+
+        // Nonce placeholders should be removed when CSP is disabled
+        $this->assertStringNotContainsString('{csp-script-nonce}', $actual);
+        $this->assertStringNotContainsString('{csp-style-nonce}', $actual);
+        $this->assertStringContainsString('<script >console.log("test")</script>', $actual);
+        $this->assertStringContainsString('<style >.test{}</style>', $actual);
+    }
+
+    public function testSendRemovesCustomNoncePlaceholdersWhenCSPDisabled(): void
+    {
+        $appConfig             = new App();
+        $appConfig->CSPEnabled = false;
+
+        // Create custom CSP config with custom nonce tags
+        $cspConfig                 = new \Config\ContentSecurityPolicy();
+        $cspConfig->scriptNonceTag = '{custom-script-tag}';
+        $cspConfig->styleNonceTag  = '{custom-style-tag}';
+
+        $response = new Response($appConfig);
+        $response->pretend(true);
+
+        // Inject the custom CSP config
+        $reflection = new \ReflectionClass($response);
+        $cspProperty = $reflection->getProperty('CSP');
+        $cspProperty->setValue($response, new ContentSecurityPolicy($cspConfig));
+
+        $body = '<html><script {custom-script-tag}>test()</script><style {custom-style-tag}>.x{}</style></html>';
+        $response->setBody($body);
+
+        ob_start();
+        $response->send();
+        $actual = ob_get_contents();
+        ob_end_clean();
+
+        // Custom nonce placeholders should be removed when CSP is disabled
+        $this->assertStringNotContainsString('{custom-script-tag}', $actual);
+        $this->assertStringNotContainsString('{custom-style-tag}', $actual);
+        $this->assertStringContainsString('<script >test()</script>', $actual);
+        $this->assertStringContainsString('<style >.x{}</style>', $actual);
+    }
+
+    public function testSendWithCSPDisabledDoesNotAffectBodyWithoutNonceTags(): void
+    {
+        $config             = new App();
+        $config->CSPEnabled = false;
+
+        $response = new Response($config);
+        $response->pretend(true);
+
+        $body = '<html><script>console.log("test")</script></html>';
+        $response->setBody($body);
+
+        ob_start();
+        $response->send();
+        $actual = ob_get_contents();
+        ob_end_clean();
+
+        // Body without nonce tags should remain unchanged
+        $this->assertSame($body, $actual);
+    }
 }