{"schema_version":"1.7.5","id":"GHSA-f4g9-h89h-jgv9","published":"2021-01-21T14:12:16Z","modified":"2026-03-13T22:01:03.537120Z","aliases":["CVE-2021-21238","PYSEC-2021-48"],"related":["CVE-2021-21238"],"summary":"SAML XML Signature wrapping in PySAML2","details":"### Impact\n\nAll users of pysaml2 that use the default `CryptoBackendXmlSec1` backend and need to verify signed SAML documents are impacted. `pysaml2 <= 6.4.1` does not validate the SAML document against an XML schema. This allows invalid XML documents to trick the verification process, by presenting elements with a valid signature inside elements whose content has been malformed. The verification is offloaded to `xmlsec1` and `xmlsec1` will not validate every signature in the given document, but only the first it finds in the given scope.\n\n### Patches\n\nUsers should upgrade to pysaml2 `v6.5.0`.\n\n### Workarounds\n\nNo workaround provided at this point.\n\n### References\n\nNo references provided at this point.\n\n### Credits\n\n- Victor Schönfelder Garcia (isits AG International School of IT Security)\n- Juraj Somorovsky (Paderborn University)\n- Vladislav Mladenov (Ruhr University Bochum)\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n* Open an issue in [pysaml2](https://github.com/IdentityPython/pysaml2)\n* Email us at [the incident-response address](mailto:incident-response@idpy.org)","affected":[{"package":{"name":"pysaml2","ecosystem":"PyPI","purl":"pkg:pypi/pysaml2"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.5.0"}]}],"versions":["0.4.3","1.0.1","1.0.2","1.0.3","1.1.0","2.0.0","2.1.0","2.2.0","2.3.0","2.4.0","3.0.0","3.0.2","4.0.0","4.0.1","4.0.2","4.0.3","4.0.4","4.0.5","4.0.5rc1","4.1.0","4.2.0","4.3.0","4.4.0","4.5.0","4.6.0","4.6.1","4.6.2","4.6.3","4.6.4","4.6.5","4.7.0","4.8.0","4.9.0","5.0.0","5.1.0","5.2.0","5.3.0","5.4.0","6.0.0","6.1.0","6.2.0","6.3.0","6.3.1","6.4.0","6.4.1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/01/GHSA-f4g9-h89h-jgv9/GHSA-f4g9-h89h-jgv9.json"}}],"references":[{"type":"WEB","url":"https://github.com/IdentityPython/pysaml2/security/advisories/GHSA-f4g9-h89h-jgv9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21238"},{"type":"WEB","url":"https://github.com/IdentityPython/pysaml2/commit/1d8fd268f5bf887480a403a7a5ef8f048157cc14"},{"type":"PACKAGE","url":"https://github.com/IdentityPython/pysaml2"},{"type":"WEB","url":"https://github.com/IdentityPython/pysaml2/releases/tag/v6.5.0"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/pysaml2/PYSEC-2021-48.yaml"},{"type":"WEB","url":"https://pypi.org/project/pysaml2"}],"database_specific":{"cwe_ids":["CWE-347"],"github_reviewed":true,"github_reviewed_at":"2021-01-21T14:11:38Z","nvd_published_at":"2021-01-21T15:15:00Z","severity":"MODERATE"},"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N"}]}