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Net-SAML2-0.55
⭐ Starred 8 / Net::SAML2::Binding::Redirect
Security Advisories (3)
CVE-2026-18089 (2026-08-03)

Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass by verifying responses against the response-embedded certificate in verify_xml when no trust anchor is configured. verify_xml in Net::SAML2::Role::VerifyXML runs "return if !$anchors && !$cacert;" as soon as the XML::Sig check succeeds, and that check uses the X.509 certificate taken from the response's own dsig:KeyInfo/dsig:X509Certificate element, so an unanchored response is checked only against the key it carries. Binding::POST declares cacert as an optional Maybe[Str] with no default, so a POST binding built without one takes that path, and _verify_encrypted_assertion returns early the same way with "return $xml unless $cacert;". Any caller that constructs Binding::POST or calls Assertion->new_from_xml without a cacert, cert_text, or anchors argument accepts a response signed by an attacker generated key whose self-signed certificate is embedded in that response, authenticating an arbitrary assertion.

CVE-2026-18092 (2026-08-03)

Net::SAML2 versions before 0.86 for Perl allow SAML authentication bypass via XML signature wrapping because new_from_xml reads assertion identity with document-wide XPath instead of the signed subtree. new_from_xml reads the NameID, attribute values, SessionIndex, audience and other identity fields with document-wide XPath, such as //saml:Assertion/saml:AttributeStatement/saml:Attribute and //saml:Subject/saml:NameID, which select the first matching element in document order rather than the element covered by the verified signature. handle_response confirms that a signature is present and, when a cacert is configured, that it chains to the CA, but XML::Sig verifies only the element named by the signature's Reference URI, so unsigned sibling assertions in the same document are not covered. An attacker who holds any one IdP-signed assertion can add an unsigned attacker-authored assertion earlier in document order; the signature still verifies and the document-order XPath returns the attacker's NameID and attributes. Any caller that passes an untrusted Response to new_from_xml can accept identity fields from an assertion the IdP never signed, even when a cacert trust anchor is configured, so a party holding one valid IdP-signed assertion can authenticate as an arbitrary user.

CVE-2026-18108 (2026-08-03)

Net::SAML2 versions before 0.86 for Perl allow authentication bypass because _verify_encrypted_assertion accepts an EncryptedAssertion whose decrypted content carries no signature. _verify_encrypted_assertion decrypts the EncryptedAssertion and returns it as verified when it carries no signature, via "return $xml unless $xpath->exists('dsig:Signature', $assert);". The signature check and the trust anchor check that follow run only when a signature is present, so a decrypted assertion with no dsig:Signature element reaches new_from_xml unverified and its NameID and attributes are read into the assertion object. An SP's encryption certificate is published in its SAML metadata so the IdP can encrypt to it, so any party can encrypt an unsigned assertion to that certificate, wrap it in a samlp:Response, and post it to the assertion consumer service. Any caller that configures a decryption key_file, and so accepts EncryptedAssertions, takes identity fields from an assertion that no trust anchor covers, and an unauthenticated party can authenticate as an arbitrary user. Callers with no key_file configured do not decrypt and are unaffected.

NAME

Net::SAML2::Binding::Redirect - Net::SAML2::Binding::Redirect - HTTP Redirect binding for SAML

VERSION

version 0.55

SYNOPSIS

my $redirect = Net::SAML2::Binding::Redirect->new(
  key     => '/path/to/SPsign-nopw-key.pem',		# Service Provider (SP) private key
  url     => $sso_url,							# Service Provider Single Sign Out URL
  param   => 'SAMLRequest' OR 'SAMLResponse',		# Type of request
  cert    => $idp->cert('signing')				# Identity Provider (IdP) certificate
  sig_hash => 'sha1', 'sha224', 'sha256', 'sha384', 'sha512'  # Signature to sign request
);

my $url = $redirect->sign($authnreq);

my $ret = $redirect->verify($url);

NAME

Net::SAML2::Binding::Redirect

METHODS

new( ... )

Constructor. Creates an instance of the Redirect binding.

Arguments:

key

The SP's (Service Provider) also known as your application's signing key that your application uses to sign the AuthnRequest. Some IdPs may not verify the signature.

cert

IdP's (Identity Provider's) certificate that is used to verify a signed Redirect from the IdP. It is used to verify the signature of the Redirect response.

url

IdP's SSO (Single Sign Out) service url for the Redirect binding

param

query param name to use (SAMLRequest, SAMLResponse)

sig_hash

RSA hash to use to sign request

Supported:

sha1, sha224, sha256, sha384, sha512

sha1 is current default but will change by version 44

sls_force_lcase_url_encoding

Specifies that the IdP requires the encoding of a URL to be in lowercase. Necessary for a HTTP-Redirect of a LogoutResponse from Azure in particular. True (1) or False (0). Some web frameworks and underlying http requests assume that the encoding should be in the standard uppercase (%2F not %2f)

sls_double_encoded_response

Specifies that the IdP response sent to the HTTP-Redirect is double encoded. The double encoding requires it to be decoded prior to processing.

sign( $request, $relaystate )

Signs the given request, and returns the URL to which the user's browser should be redirected.

Accepts an optional RelayState parameter, a string which will be returned to the requestor when the user returns from the authentication process with the IdP.

verify( $url )

Decode a Redirect binding URL.

Verifies the signature on the response.

AUTHOR

Chris Andrews <chrisa@cpan.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2022 by Chris Andrews and Others, see the git log.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.