GHSA-f4g9-h89h-jgv9

SAML XML Signature wrapping in PySAML2

Source: GitHub Advisory Database (reviewed) Moderate CVE-2021-21238

Packages

Ecosystem	Package	Affected	Fixed in
PyPI	pysaml2	< 6.5.0	6.5.0

Details

As written in the advisory (Markdown source, shown as plain text).

### Impact All users of pysaml2 that use the default `CryptoBackendXmlSec1` backend and need to verify signed SAML documents are impacted. `pysaml2 <= 6.4.1` does not validate the SAML document against an XML schema. This allows invalid XML documents to trick the verification process, by presenting elements with a valid signature inside elements whose content has been malformed. The verification is offloaded to `xmlsec1` and `xmlsec1` will not validate every signature in the given document, but only the first it finds in the given scope. ### Patches Users should upgrade to pysaml2 `v6.5.0`. ### Workarounds No workaround provided at this point. ### References No references provided at this point. ### Credits - Victor Schönfelder Garcia (isits AG International School of IT Security) - Juraj Somorovsky (Paderborn University) - Vladislav Mladenov (Ruhr University Bochum) ### For more information If you have any questions or comments about this advisory: * Open an issue in [pysaml2](https://github.com/IdentityPython/pysaml2) * Email us at [the incident-response address](mailto:[email protected])

References

External links from the advisory. They lead to third-party sites.