CVE-2021-21238

CVE-2021-21238 describes an improper cryptographic signature verification vulnerability in PySAML2 versions prior to 6.5.0, affecting all users who validate signed SAML documents. This flaw, a variant of XML Signature wrapping, allows invalid XML documents to be processed, potentially tricking PySAML2 with a wrapped signature. With a CVSS score of 6.5 (Medium), it can be exploited remotely with low attack complexity, requiring user interaction, and primarily impacts integrity (I:H). There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.