CVE-2021-21239

Public Exploit
Open default xmlsec1 key-type preference

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.

Category

6.5
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 1.23% Top 25%
Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory github.com Third-Party Advisory debian.org Third-Party Advisory pypi.org Third-Party Advisory aleksey.com
Affected: IdentityPython pysaml2
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-21239?
CVE-2021-21239 has been scored as a medium severity vulnerability.
How to fix CVE-2021-21239?
To fix CVE-2021-21239, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-21239 being actively exploited in the wild?
It is possible that CVE-2021-21239 is being exploited or will be exploited in a near future based on public information. According to its EPSS score, there is a ~1% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-21239?
CVE-2021-21239 affects IdentityPython pysaml2.
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