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. Users of pysaml2 that use the default CryptoBackendXmlSec1 backend and need to verify signed SAML documents are impacted. PySAML2 does not ensure that a signed SAML document is correctly signed. The default CryptoBackendXmlSec1 backend is using the xmlsec1 binary to verify the signature of signed SAML documents, but by default xmlsec1 accepts any type of key found within the given document. xmlsec1 needs to be configured explicitly to only use only _x509 certificates_ for the verification process of the SAML document signature. This is fixed in PySAML2 6.5.0.
CVSS Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Pysaml2 Project | Pysaml2 | < 6.5.0 |
| Debian | Debian Linux | 9.0 |
Related Weaknesses (CWE)
References
- https://github.com/IdentityPython/pysaml2/commit/46578df0695269a16f1c94171f14298PatchThird Party Advisory
- https://github.com/IdentityPython/pysaml2/releases/tag/v6.5.0Third Party Advisory
- https://github.com/IdentityPython/pysaml2/security/advisories/GHSA-5p3x-r448-pc6Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/02/msg00038.htmlMailing ListThird Party Advisory
- https://pypi.org/project/pysaml2ProductThird Party Advisory
- https://www.aleksey.com/pipermail/xmlsec/2013/009717.htmlExploitMailing ListThird Party Advisory
- https://github.com/IdentityPython/pysaml2/commit/46578df0695269a16f1c94171f14298PatchThird Party Advisory
- https://github.com/IdentityPython/pysaml2/releases/tag/v6.5.0Third Party Advisory
- https://github.com/IdentityPython/pysaml2/security/advisories/GHSA-5p3x-r448-pc6Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/02/msg00038.htmlMailing ListThird Party Advisory
- https://pypi.org/project/pysaml2ProductThird Party Advisory
- https://www.aleksey.com/pipermail/xmlsec/2013/009717.htmlExploitMailing ListThird Party Advisory
FAQ
What is CVE-2021-21239?
CVE-2021-21239 is a vulnerability with a CVSS score of 6.5 (MEDIUM). PySAML2 is a pure python implementation of SAML Version 2 Standard. PySAML2 before 6.5.0 has an improper verification of cryptographic signature vulnerability. Users of pysaml2 that use the default Cr...
How severe is CVE-2021-21239?
CVE-2021-21239 has been rated MEDIUM with a CVSS base score of 6.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2021-21239?
Check the references section above for vendor advisories and patch information. Affected products include: Pysaml2 Project Pysaml2, Debian Debian Linux.