CVE-2021-21238: SAML XML Signature wrapping in PySAML2

CVE-2021-21238 · Severity: low · CVSS 3.1 · Published 2021-01-21

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.

Technologies: pysaml2 (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2021-21238 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2021-21238 being exploited in the wild.
How severe is CVE-2021-21238?
Low severity, with a CVSS score of 3.1, published 21 January 2021.
Which products and versions are affected?
pysaml2 (PyPI) ECOSYSTEM:introduced=0,fixed=6.5.0, GIT:introduced=0,fixed=1d8fd268f5bf887480a403a7a5ef8f048157cc14|ECOSYSTEM:introduced=0,fixed=6.5.0.
Is there a fix for CVE-2021-21238?
Yes. pysaml2 (PyPI): upgrade to 6.5.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2021-21238?
Check whether you run pysaml2 (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • pysaml2 (PyPI): upgrade to 6.5.0 or later
    pip install "pysaml2>=6.5.0"

Affected products

  • pysaml2 (PyPI) ECOSYSTEM:introduced=0,fixed=6.5.0, GIT:introduced=0,fixed=1d8fd268f5bf887480a403a7a5ef8f048157cc14|ECOSYSTEM:introduced=0,fixed=6.5.0

Identifiers

  • CVE-2021-21238
  • GHSA-f4g9-h89h-jgv9
  • PYSEC-2021-48

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