fix: fix array handling in ContentSecurityPolicy::setDefaultSrc() and add addDefaultSrc()

system/HTTP/ContentSecurityPolicy.php

@@ -521,12 +521,30 @@ public function addConnectSrc($uri, ?bool $explicitReporting = null)
      * @see http://www.w3.org/TR/CSP/#directive-default-src
      *
      * @param list<string>|string $uri
+     */
+    public function addDefaultSrc(array|string $uri, ?bool $explicitReporting = null): static
+    {
+        $this->addOption($uri, 'defaultSrc', $explicitReporting ?? $this->reportOnly);
+
+        return $this;
+    }
+
+    /**
+     * Sets the `default-src` directive, replacing any existing sources.
+     *
+     * `default-src` is the URI that is used for many of the settings when
+     * no other source has been set.
+     *
+     * @see http://www.w3.org/TR/CSP/#directive-default-src
+     *
+     * @param list<string>|string $uri
      *
      * @return $this
      */
     public function setDefaultSrc($uri, ?bool $explicitReporting = null)
     {
-        $this->defaultSrc = [(string) $uri => $explicitReporting ?? $this->reportOnly];
+        $this->defaultSrc = [];
+        $this->addDefaultSrc($uri, $explicitReporting);
 
         return $this;
     }

tests/system/HTTP/ContentSecurityPolicyTest.php

@@ -617,6 +617,50 @@ public function testDefaultSrc(): void
         $this->assertContains('default-src iffy.com', $this->getCspDirectives($header));
     }
 
+    #[PreserveGlobalState(false)]
+    #[RunInSeparateProcess]
+    public function testDefaultSrcRich(): void
+    {
+        $this->csp->reportOnly(false);
+        $this->csp->setDefaultSrc(['self', 'maybe.com', 'iffy.com']);
+        $this->assertTrue($this->work());
+
+        $header = $this->getHeaderEmitted('Content-Security-Policy');
+        $this->assertIsString($header);
+        $this->assertContains("default-src 'self' maybe.com iffy.com", $this->getCspDirectives($header));
+    }
+
+    #[PreserveGlobalState(false)]
+    #[RunInSeparateProcess]
+    public function testAddDefaultSrc(): void
+    {
+        $this->csp->addDefaultSrc('maybe.com');
+        $this->csp->addDefaultSrc('iffy.com', true);
+        $this->assertTrue($this->work());
+
+        $header = $this->getHeaderEmitted('Content-Security-Policy-Report-Only');
+        $this->assertIsString($header);
+        $this->assertContains('default-src iffy.com', $this->getCspDirectives($header));
+
+        $header = $this->getHeaderEmitted('Content-Security-Policy');
+        $this->assertIsString($header);
+        $this->assertContains('default-src maybe.com', $this->getCspDirectives($header));
+    }
+
+    #[PreserveGlobalState(false)]
+    #[RunInSeparateProcess]
+    public function testAddDefaultSrcAppends(): void
+    {
+        $this->csp->reportOnly(false);
+        $this->csp->setDefaultSrc('maybe.com');
+        $this->csp->addDefaultSrc('iffy.com');
+        $this->assertTrue($this->work());
+
+        $header = $this->getHeaderEmitted('Content-Security-Policy');
+        $this->assertIsString($header);
+        $this->assertContains('default-src maybe.com iffy.com', $this->getCspDirectives($header));
+    }
+
     #[PreserveGlobalState(false)]
     #[RunInSeparateProcess]
     public function testReportURI(): void

user_guide_src/source/changelogs/v4.7.6.rst

@@ -24,6 +24,8 @@ Message Changes
 Changes
 *******
 
+- **HTTP:** Added ``ContentSecurityPolicy::addDefaultSrc()`` to allow appending sources to the ``default-src`` directive.
+
 ************
 Deprecations
 ************
@@ -35,6 +37,7 @@ Bugs Fixed
 - **Commands:** Fixed a bug where generator commands did not sort the imports of a template with CRLF line endings.
 - **Format:** Fixed ``XMLFormatter`` so that an array key that becomes empty after sanitization no longer triggers a ``ValueError``; the fallback tag name ``item`` is used instead. Values that cannot be converted to a string, such as objects not implementing ``Stringable``, now throw a ``FormatException`` instead of a fatal ``Error``.
 - **Helpers:** Fixed a regression in v4.7.5 where ``set_value()`` threw a ``TypeError`` when the default value was not a string or an array, such as an integer, a float, ``null``, or a ``Stringable`` object. Such values are now converted to a string.
+- **HTTP:** Fixed a bug in ``ContentSecurityPolicy::setDefaultSrc()`` where passing an array of URIs resulted in an invalid ``'Array'`` directive.
 - **HTTP:** Fixed stale ``$_REQUEST`` values after ``SiteURIFactory`` normalizes GET parameters, so ``Validation::withRequest()`` reads the normalized values while unrelated REQUEST entries are preserved.
 - **HTTP:** Fixed a bug where ``IncomingRequest::isSecure()`` did not recognize ``https`` in the ``X-Forwarded-Proto`` header from a trusted proxy when the value contained uppercase letters or surrounding whitespace, or was represented as a single-element array.
 - **Security:** Fixed a bug where a valid JSON request body that is not an object (for example a JSON array) was corrupted after CSRF verification when the token was sent via the ``X-CSRF-TOKEN`` header.