Shibboleth consortium reports:
An updated version of the XMLTooling library that is part of the
OpenSAML and Shibboleth Service Provider software is now available
which corrects a server-side request forgery (SSRF) vulnerability.
Including certain legal but "malicious in intent" content in the
KeyInfo element defined by the XML Signature standard will result
in attempts by the SP's shibd process to dereference untrusted
While the content of the URL must be supplied within the message
and does not include any SP internal state or dynamic content,
there is at minimum a risk of denial of service, and the attack
could be combined with others to create more serious vulnerabilities
in the future.