{"id":"CVE-2021-21238","aliases":["GHSA-f4g9-h89h-jgv9","PYSEC-2021-48"],"url":"https://o3.security/vulnerability/CVE-2021-21238","summary":"SAML XML Signature wrapping in PySAML2","details":"PySAML2 is a pure python implementation of SAML Version 2 Standard. PySAML2 before 6.5.0 has an improper verification of cryptographic signature vulnerability. All users of pysaml2 that need to validate signed SAML documents are impacted. The vulnerability is a variant of XML Signature wrapping because it did not validate the SAML document against an XML schema. This allowed invalid XML documents to be processed and such a document can trick pysaml2 with a wrapped signature. This is fixed in PySAML2 6.5.0.","published":"2021-01-21T15:15:14.110Z","modified":"2026-08-27T08:14:32.843096Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"pysaml2","fixedVersion":"6.5.0"}],"fix":{"url":"https://github.com/IdentityPython/pysaml2/commit/1d8fd268f5bf887480a403a7a5ef8f048157cc14","label":"IdentityPython/pysaml2@1d8fd26"},"references":[{"type":"ADVISORY","url":"https://github.com/IdentityPython/pysaml2/releases/tag/v6.5.0"},{"type":"ADVISORY","url":"https://github.com/IdentityPython/pysaml2/security/advisories/GHSA-f4g9-h89h-jgv9"},{"type":"FIX","url":"https://github.com/IdentityPython/pysaml2/commit/1d8fd268f5bf887480a403a7a5ef8f048157cc14"},{"type":"PACKAGE","url":"https://pypi.org/project/pysaml2"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-27T08:14:32.843096Z"}}