CVE-2021-21239

PySAML2 is a pure python implementation of SAML Version 2 Standard. PySAML2
before 6.5.0 has an improper verification of cryptographic signature
vulnerability. Users of pysaml2 that use the default CryptoBackendXmlSec1
backend and need to verify signed SAML documents are impacted. PySAML2 does
not ensure that a signed SAML document is correctly signed. The default
CryptoBackendXmlSec1 backend is using the xmlsec1 binary to verify the
signature of signed SAML documents, but by default xmlsec1 accepts any type
of key found within the given document. xmlsec1 needs to be configured
explicitly to only use only x509 certificates for the verification
process of the SAML document signature. This is fixed in PySAML2 6.5.0.

Bugs

• <http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=980772&gt;