CVE-2026-18108: critical vulnerability in TIMLEGGE Net::SAML2
Net::SAML2 versions before 0.86 for Perl allow authentication bypass because _verify_encrypted_assertion accepts an EncryptedAssertion whose decrypted content carries no signature
Published
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28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.8epss 0.3%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
TIMLEGGE · Net::SAML2Related CVEs — TIMLEGGE Net::SAML2
In the same product, most dangerous first.
CVE-2026-18092HIGHNet::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 subtreeEPSS 0.3%CVE-2026-18089HIGHNet::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 configuredEPSS 0.2%