{"id":"CVE-2021-21238","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-21238","generatedAt":"2026-10-27T23:43:26.214Z","title":"PySAML2 before 6.5.0 has an improper verification of cryptographic signature vulnerability.","description":"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":"2021-01-21T15:15:14.000Z","lastModified":"2026-06-17T03:35:06.000Z","status":"Modified","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","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"},"cwe":["CWE-347"],"affected":["pysaml2 project/pysaml2"],"epss":{"score":0.01096,"percentile":0.6533,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (1.10%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/IdentityPython/pysaml2/commit/1d8fd268f5bf887480a403a7a5ef8f048157cc14","tags":["Patch","Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/IdentityPython/pysaml2/releases/tag/v6.5.0","tags":["Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/IdentityPython/pysaml2/security/advisories/GHSA-f4g9-h89h-jgv9","tags":["Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://pypi.org/project/pysaml2","tags":["Product","Third Party Advisory"],"source":"security-advisories@github.com"},{"url":"https://github.com/IdentityPython/pysaml2/commit/1d8fd268f5bf887480a403a7a5ef8f048157cc14","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/IdentityPython/pysaml2/releases/tag/v6.5.0","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/IdentityPython/pysaml2/security/advisories/GHSA-f4g9-h89h-jgv9","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://pypi.org/project/pysaml2","tags":["Product","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-21238","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}