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Fix confusion of the root-node when validating a signature #424

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Fix confusion of the root-node when validating a signature #424

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b39c171
Fix confusion of the root-node when validating a signature
tvdijen Aug 13, 2026
b70f84b
No-op: improve comments and method name
tvdijen Aug 15, 2026
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6 changes: 5 additions & 1 deletion src/XML/saml/Assertion.php
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
use SimpleSAML\SAML2\XML\EncryptableElementTrait;
use SimpleSAML\SAML2\XML\SignableElementTrait;
use SimpleSAML\SAML2\XML\SignedElementTrait;
use SimpleSAML\XML\DOMDocumentFactory;
use SimpleSAML\XML\SchemaValidatableElementInterface;
use SimpleSAML\XML\SchemaValidatableElementTrait;
use SimpleSAML\XMLSchema\Exception\InvalidDOMElementException;
Expand Down Expand Up @@ -326,7 +327,10 @@ public static function fromXML(Dom\Element $xml): static
if (!empty($signature)) {
$assertion->setSignature($signature[0]);
$assertion->wasSignedAtConstruction = true;
$assertion->setXML($xml);

$doc = DOMDocumentFactory::create();
$doc->appendChild($doc->importNode($xml, true));
$assertion->setXML($doc->documentElement);
}

return $assertion;
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31 changes: 19 additions & 12 deletions tests/Vulnerabilities/GoldenSAMLResponseTest.php
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Expand Up @@ -16,40 +16,47 @@
use function dirname;

/**
* CVE-2025-66475
*
* @package simplesamlphp/saml2
*/
#[Group('vulnerabilities')]
final class GoldenSAMLResponseTest extends TestCase
{
/**
* CVE-2025-66475 / Void Canonicalization ("Golden SAML Response")
*
* A relative namespace on an ancestor causes libxml2 C14N to fail.
* After the fix this must be treated as fatal; the signature must not
* be accepted (even though DigestValue is the SHA-256 of the empty string).
*/
public function testSignedResponseWithStrayXmlnsThrowsAnException(): void
public function testGoldenSAMLResponseWithRelativeXmlnsIsRejected(): void
{
$doc = DOMDocumentFactory::fromFile(
dirname(__DIR__, 1) . '/resources/xml/vulnerabilities/CVE-2025-66475.xml',
);

$response = Response::fromXML($doc->documentElement);
$assertion = $response->getAssertions()[0];
/** @var \SimpleSAML\XMLSecurity\XML\ds\X509Data $data */
$data = $assertion->getSignature()->getKeyInfo()->getInfo()[0];

// Key material taken from the Signature in the fixture
/** @var \SimpleSAML\XMLSecurity\XML\ds\X509Data $x509Data */
$x509Data = $assertion->getSignature()->getKeyInfo()->getInfo()[0];
$cert = $x509Data->getData()[0]->getContent()->getValue();

$alg = $assertion->getSignature()
->getSignedInfo()
->getSignatureMethod()
->getAlgorithm()
->getValue();

$verifier = (new SignatureAlgorithmFactory())->getAlgorithm(
$assertion->getSignature()->getSignedInfo()->getSignatureMethod()->getAlgorithm()->getValue(),
$alg,
new PublicKey(
new PEM(
PEM::TYPE_PUBLIC_KEY,
$data->getData()[0]->getContent()->getValue(),
),
new PEM(PEM::TYPE_PUBLIC_KEY, $cert),
),
);

$this->expectException(CanonicalizationFailedException::class);

// When PHP 8.5 becomes the minimum:
// (void)@$assertion->verify($verifier);
@$assertion->verify($verifier);
}
}
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