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[HtmlSanitizer] Use the native HTML5 parser when using PHP 8.4+ #61366

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Merged
nicolas-grekas merged 1 commit into from
Aug 12, 2025
Merged

[HtmlSanitizer] Use the native HTML5 parser when using PHP 8.4+ #61366

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2 changes: 1 addition & 1 deletion .github/workflows/psalm.yml
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Expand Up @@ -20,7 +20,7 @@ jobs:
runs-on: ubuntu-24.04

env:
php-version: '8.2'
php-version: '8.4'
steps:
- name: Setup PHP
uses: shivammathur/setup-php@v2
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12 changes: 10 additions & 2 deletions UPGRADE-7.4.md
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Expand Up @@ -16,7 +16,7 @@ Cache
Console
-------

* Deprecate `Symfony\Component\Console\Application::add()` in favor of `Symfony\Component\Console\Application::addCommand()`
* Deprecate `Symfony\Component\Console\Application::add()` in favor of `addCommand()`

DependencyInjection
-------------------
Expand All @@ -32,7 +32,15 @@ DoctrineBridge
FrameworkBundle
---------------

* Deprecate `Symfony\Bundle\FrameworkBundle\Console\Application::add()` in favor of `Symfony\Bundle\FrameworkBundle\Console\Application::addCommand()`
* Deprecate `Symfony\Bundle\FrameworkBundle\Console\Application::add()` in favor of `addCommand()`

HtmlSanitizer
-------------

* Use the native HTML5 parser when using PHP 8.4+
* Deprecate `MastermindsParser`; use `NativeParser` instead
* [BC BREAK] `ParserInterface::parse()` can now return `\Dom\Node|\DOMNode|null` instead of just `\DOMNode|null`
* Add argument `$context` to `ParserInterface::parse()`

HttpClient
----------
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8 changes: 8 additions & 0 deletions src/Symfony/Component/HtmlSanitizer/CHANGELOG.md
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@@ -1,6 +1,14 @@
CHANGELOG
=========

7.4
---

* Use the native HTML5 parser when using PHP 8.4+
* Deprecate `MastermindsParser`; use `NativeParser` instead
* [BC BREAK] `ParserInterface::parse()` can now return `\Dom\Node|\DOMNode|null` instead of just `\DOMNode|null`
* Add argument `$context` to `ParserInterface::parse()`

7.2
---

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21 changes: 9 additions & 12 deletions src/Symfony/Component/HtmlSanitizer/HtmlSanitizer.php
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Expand Up @@ -12,6 +12,7 @@
namespace Symfony\Component\HtmlSanitizer;

use Symfony\Component\HtmlSanitizer\Parser\MastermindsParser;
use Symfony\Component\HtmlSanitizer\Parser\NativeParser;
use Symfony\Component\HtmlSanitizer\Parser\ParserInterface;
use Symfony\Component\HtmlSanitizer\Reference\W3CReference;
use Symfony\Component\HtmlSanitizer\TextSanitizer\StringSanitizer;
Expand All @@ -34,24 +35,20 @@ public function __construct(
?ParserInterface $parser = null,
) {
$this->config = $config;
$this->parser = $parser ?? new MastermindsParser();
$this->parser = $parser ?? (\PHP_VERSION_ID < 80400 ? new MastermindsParser() : new NativeParser());
}

public function sanitize(string $input): string
{
return $this->sanitizeWithContext(W3CReference::CONTEXT_BODY, $input);
return $this->sanitizeFor(W3CReference::CONTEXT_BODY, $input);
}

public function sanitizeFor(string $element, string $input): string
{
return $this->sanitizeWithContext(
W3CReference::CONTEXTS_MAP[StringSanitizer::htmlLower($element)] ?? W3CReference::CONTEXT_BODY,
$input
);
}
$element = StringSanitizer::htmlLower($element);
$context = W3CReference::CONTEXTS_MAP[$element] ?? W3CReference::CONTEXT_BODY;
$element = isset(W3CReference::BODY_ELEMENTS[$element]) ? $element : $context;

private function sanitizeWithContext(string $context, string $input): string
{
// Text context: early return with HTML encoding
if (W3CReference::CONTEXT_TEXT === $context) {
return StringSanitizer::encodeHtmlEntities($input);
Expand All @@ -71,11 +68,11 @@ private function sanitizeWithContext(string $context, string $input): string
return '';
}

// Remove NULL character
$input = str_replace(\chr(0), '', $input);
// Remove NULL character and HTML entities for null byte
$input = str_replace([\chr(0), '&#0;', '&#x00;', '&#X00;', '&#000;'], '�', $input);
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@xabbuh xabbuh Aug 13, 2025

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$input = str_replace([\chr(0), '&#0;', '&#x00;', '&#X00;', '&#000;'], '', $input);

Why not like this?

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@nicolas-grekas nicolas-grekas Aug 13, 2025

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The native parser already turns variants of &#0; into �. We cannot really hook there. I think this is what the spec says to do.
Also: removing characters is a know vector for attacks, because it breaks content scanners.


// Parse as HTML
if (!$parsed = $this->parser->parse($input)) {
if ('' === trim($input) || !$parsed = $this->parser->parse($input, $element)) {
return '';
}

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7 changes: 6 additions & 1 deletion src/Symfony/Component/HtmlSanitizer/Parser/MastermindsParser.php
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Expand Up @@ -14,15 +14,20 @@
use Masterminds\HTML5;

/**
* @deprecated since Symfony 7.4, use `NativeParser` instead
*
* @author Titouan Galopin <galopintitouan@gmail.com>
*/
final class MastermindsParser implements ParserInterface
{
public function __construct(private array $defaultOptions = [])
{
if (\PHP_VERSION_ID >= 80400) {
trigger_deprecation('symfony/html-sanitizer', '7.4', '"%s" is deprecated since Symfony 7.4 and will be removed in 8.0. Use the "NativeParser" instead.', self::class);
}
}

public function parse(string $html): ?\DOMNode
public function parse(string $html, string $context = 'body'): ?\DOMNode
{
return (new HTML5($this->defaultOptions))->loadHTMLFragment($html);
}
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33 changes: 33 additions & 0 deletions src/Symfony/Component/HtmlSanitizer/Parser/NativeParser.php
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@@ -0,0 +1,33 @@
<?php

/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/

namespace Symfony\Component\HtmlSanitizer\Parser;

/**
* Parser using PHP 8.4's new Dom API.
*/
final class NativeParser implements ParserInterface
{
public function __construct()
{
if (\PHP_VERSION_ID < 80400) {
throw new \LogicException(self::class.' requires PHP 8.4 or higher.');
}
}

public function parse(string $html, string $context = 'body'): ?\Dom\Node
{
$document = @\Dom\HTMLDocument::createFromString(\sprintf('<!DOCTYPE html><%s>%s</%1$s>', $context, $html));
$element = $document->getElementsByTagName($context)->item(0);

return $element->hasChildNodes() ? $element : null;
}
}
4 changes: 3 additions & 1 deletion src/Symfony/Component/HtmlSanitizer/Parser/ParserInterface.php
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Expand Up @@ -22,6 +22,8 @@ interface ParserInterface
* Parse a given string and returns a DOMNode tree.
*
* This method must return null if the string cannot be parsed as HTML.
*
* @param string $context The name of the context element in which the HTML is parsed
*/
public function parse(string $html): ?\DOMNode;
public function parse(string $html/* , string $context = 'body' */): \Dom\Node|\DOMNode|null;
}
74 changes: 59 additions & 15 deletions src/Symfony/Component/HtmlSanitizer/Tests/HtmlSanitizerAllTest.php
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Expand Up @@ -64,8 +64,11 @@ public static function provideSanitizeHead()
}

#[DataProvider('provideSanitizeBody')]
public function testSanitizeBody(string $input, string $expected)
public function testSanitizeBody(string $input, string $expected, ?string $legacyExpected = null)
{
if (\PHP_VERSION_ID < 80400) {
$expected = $legacyExpected ?? $expected;
}
$this->assertSame($expected, $this->createSanitizer()->sanitize($input));
}

Expand All @@ -83,6 +86,7 @@ public static function provideSanitizeBody()
],
[
'< Hello',
'&lt; Hello',
' Hello',
],
[
Expand Down Expand Up @@ -127,6 +131,7 @@ public static function provideSanitizeBody()
],
[
'<<a href="javascript:evil"/>a href="javascript:evil"/>',
'&lt;<a>a href&#61;&#34;javascript:evil&#34;/&gt;</a>',
'<a>a href&#61;&#34;javascript:evil&#34;/&gt;</a>',
],
[
Expand Down Expand Up @@ -163,10 +168,12 @@ public static function provideSanitizeBody()
],
[
'<<img src="javascript:evil"/>iframe src="javascript:evil"/>',
'&lt;<img />iframe src&#61;&#34;javascript:evil&#34;/&gt;',
'<img />iframe src&#61;&#34;javascript:evil&#34;/&gt;',
],
[
'<<img src="javascript:evil"/>img src="javascript:evil"/>',
'&lt;<img />img src&#61;&#34;javascript:evil&#34;/&gt;',
'<img />img src&#61;&#34;javascript:evil&#34;/&gt;',
],
[
Expand Down Expand Up @@ -211,10 +218,12 @@ public static function provideSanitizeBody()
],
[
'<IMG SRC=&#0000106&#0000097&#0000118&#0000097&#0000115&#0000099&#0000114&#0000105&#0000112&#0000116&#0000058&#0000097&#0000108&#0000101&#0000114&#0000116&#0000040&#0000039&#0000088&#0000083&#0000083&#0000039&#0000041>',
'<img />',
'<img src="&amp;#0000106&amp;#0000097&amp;#0000118&amp;#0000097&amp;#0000115&amp;#0000099&amp;#0000114&amp;#0000105&amp;#0000112&amp;#0000116&amp;#0000058&amp;#0000097&amp;#0000108&amp;#0000101&amp;#0000114&amp;#0000116&amp;#0000040&amp;#0000039&amp;#0000088&amp;#0000083&amp;#0000083&amp;#0000039&amp;#0000041" />',
],
[
'<IMG SRC=&#x6A&#x61&#x76&#x61&#x73&#x63&#x72&#x69&#x70&#x74&#x3A&#x61&#x6C&#x65&#x72&#x74&#x28&#x27&#x58&#x53&#x53&#x27&#x29>',
'<img />',
'<img src="&amp;#x6A&amp;#x61&amp;#x76&amp;#x61&amp;#x73&amp;#x63&amp;#x72&amp;#x69&amp;#x70&amp;#x74&amp;#x3A&amp;#x61&amp;#x6C&amp;#x65&amp;#x72&amp;#x74&amp;#x28&amp;#x27&amp;#x58&amp;#x53&amp;#x53&amp;#x27&amp;#x29" />',
],
[
Expand All @@ -233,10 +242,6 @@ public static function provideSanitizeBody()
'<svg/onload=alert(\'XSS\')>',
'',
],
[
'<BODY BACKGROUND="javascript:alert(\'XSS\')">',
'<body></body>',
],
[
'<BGSOUND SRC="javascript:alert(\'XSS\');">',
'<bgsound></bgsound>',
Expand Down Expand Up @@ -350,10 +355,6 @@ public static function provideSanitizeBody()
'Lorem ipsum <br>dolor sit amet <br />consectetur adipisicing.',
'Lorem ipsum <br />dolor sit amet <br />consectetur adipisicing.',
],
[
'<caption>Lorem ipsum</caption>',
'<caption>Lorem ipsum</caption>',
],
[
'<code>Lorem ipsum</code>',
'<code>Lorem ipsum</code>',
Expand Down Expand Up @@ -529,41 +530,84 @@ public static function provideSanitizeBody()
],
[
'<table>Lorem ipsum</table>',
'Lorem ipsum<table></table>',
'<table>Lorem ipsum</table>',
],
[
'<ul>Lorem ipsum</ul>',
'<ul>Lorem ipsum</ul>',
],
];

foreach ($cases as $case) {
yield $case[0] => $case;
}
}

#[DataProvider('provideSanitizeTable')]
public function testSanitizeTable(string $input, string $expected, ?string $legacyExpected = null)
{
if (\PHP_VERSION_ID < 80400) {
$expected = $legacyExpected ?? $expected;
}

$this->assertSame($expected, $this->createSanitizer()->sanitizeFor('table', $input));
}

public static function provideSanitizeTable(): iterable
{
return [
[
'<caption>Lorem ipsum</caption>',
'<caption>Lorem ipsum</caption>',
],
[
'<tbody>Lorem ipsum</tbody>',
'<tbody></tbody>',
'<tbody>Lorem ipsum</tbody>',
],
[
'<td>Lorem ipsum</td>',
'<tbody><tr><td>Lorem ipsum</td></tr></tbody>',
'<td>Lorem ipsum</td>',
],
[
'<tfoot>Lorem ipsum</tfoot>',
'<tfoot></tfoot>',
'<tfoot>Lorem ipsum</tfoot>',
],
[
'<thead>Lorem ipsum</thead>',
'<thead></thead>',
'<thead>Lorem ipsum</thead>',
],
[
'<th>Lorem ipsum</th>',
'<tbody><tr><th>Lorem ipsum</th></tr></tbody>',
'<th>Lorem ipsum</th>',
],
[
'<tr>Lorem ipsum</tr>',
'<tbody><tr></tr></tbody>',
'<tr>Lorem ipsum</tr>',
],
];
}

#[DataProvider('provideSanitizeHtml')]
public function testSanitizeHtml(string $input, string $expected)
{
$this->assertSame($expected, $this->createSanitizer()->sanitizeFor('html', $input));
}

public static function provideSanitizeHtml(): iterable
{
return [
[
'<ul>Lorem ipsum</ul>',
'<ul>Lorem ipsum</ul>',
'<BODY BACKGROUND="javascript:alert(\'XSS\')">',
'<body></body>',
],
];

foreach ($cases as $case) {
yield $case[0] => $case;
}
}

public function testUnlimitedLength()
Expand Down
8 changes: 4 additions & 4 deletions src/Symfony/Component/HtmlSanitizer/Tests/HtmlSanitizerCustomTest.php
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Expand Up @@ -25,8 +25,8 @@ public function testSanitizeForHead()
;

$this->assertSame(
' world',
(new HtmlSanitizer($config))->sanitizeFor('head', '<div style="width: 100px">Hello</div> world')
'',
(new HtmlSanitizer($config))->sanitizeFor('head', '<div style="width: 100px">Hello world</div>')
);
}

Expand Down Expand Up @@ -65,8 +65,8 @@ public function testSanitizeDeepNestedString()

public function testSanitizeNullByte()
{
$this->assertSame('Null byte', $this->sanitize(new HtmlSanitizerConfig(), "Null byte\0"));
$this->assertSame('Null byte', $this->sanitize(new HtmlSanitizerConfig(), 'Null byte&#0;'));
$this->assertSame('Null byte�', $this->sanitize(new HtmlSanitizerConfig(), "Null byte\0"));
$this->assertSame('Null byte�', $this->sanitize(new HtmlSanitizerConfig(), 'Null byte&#0;'));
}

public function testSanitizeDefaultBody()
Expand Down
4 changes: 4 additions & 0 deletions src/Symfony/Component/HtmlSanitizer/Tests/Parser/MastermindsParserTest.php
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Expand Up @@ -11,9 +11,13 @@

namespace Symfony\Component\HtmlSanitizer\Tests\Parser;

use PHPUnit\Framework\Attributes\Group;
use PHPUnit\Framework\Attributes\IgnoreDeprecations;
use PHPUnit\Framework\TestCase;
use Symfony\Component\HtmlSanitizer\Parser\MastermindsParser;

#[IgnoreDeprecations]
#[Group('legacy')]
class MastermindsParserTest extends TestCase
{
public function testParseValid()
Expand Down
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