CVE-2021-21239 Information

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 Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N

Reference

https://www.aleksey.com/pipermail/xmlsec/2013/009717.html https://pypi.org/project/pysaml2 https://github.com/IdentityPython/pysaml2/releases/tag/v6.5.0 https://github.com/IdentityPython/pysaml2/security/advisories/GHSA-5p3x-r448-pc62 https://github.com/IdentityPython/pysaml2/commit/46578df0695269a16f1c94171f1429873f90ed99 https://lists.debian.org/debian-lts-announce/2021/02/msg00038.html

Attack Complexity

LOW

Privileges Required

NONE

User Interaction Required

NONE

Scope

REQUIRED

Confidentiality Impact

UNCHANGED

Integrity Impact

NONE

Availability Impact

HIGH

Base Score

NONE

Base Severity

6.5