OneLogin PythonSAML 2.3.0 and earlier may incorrectly utilize the results of XML DOM traversal and canonicalization APIs in such a way that an attacker may be able to manipulate the SAML data without invalidating the cryptographic signature, allowing the attack to potentially bypass authentication to SAML service providers.

References

• https://nvd.nist.gov/vuln/detail/CVE-2017-11427
• https://duo.com/blog/duo-finds-saml-vulnerabilities-affecting-multiple-implementations
• GHSA-j8j8-348v-wfm3
• https://www.kb.cert.org/vuls/id/475445
• SAML-Toolkits/python-saml@fad881b