Vulnerability · Published Jan 21, 2021 · Assigned by GitHub_M
CVE-2021-21239Open default xmlsec1 key-type preference
Medium 6.5
In plain English
A medium-severity security flaw in pysaml2 from IdentityPython. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.3% (higher than 70% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | py3-saml2 | 6.5.0-r0 | ALPINE-CVE-2021-21239 |
| Alpine:v3.21 | py3-saml2 | 6.5.0-r0 | ALPINE-CVE-2021-21239 |
| Alpine:v3.22 | py3-saml2 | 6.5.0-r0 | ALPINE-CVE-2021-21239 |
| Alpine:v3.23 | py3-saml2 | 6.5.0-r0 | ALPINE-CVE-2021-21239 |
| Alpine:v3.24 | py3-saml2 | 6.5.0-r0 | ALPINE-CVE-2021-21239 |
| Debian:12 | python-pysaml2 | 6.5.1-1 | DEBIAN-CVE-2021-21239 |
| Debian:13 | python-pysaml2 | 6.5.1-1 | DEBIAN-CVE-2021-21239 |
| Debian:14 | python-pysaml2 | 6.5.1-1 | DEBIAN-CVE-2021-21239 |
| PyPI | pysaml2 | 6.5.0 | GHSA-5p3x-r448-pc62 |
| PyPI | pysaml2 | 6.5.0 | PYSEC-2021-49 |
| Ubuntu:22.04:LTS | python-pysaml2 | 6.1.0-0ubuntu2 | UBUNTU-CVE-2021-21239 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| IdentityPython | pysaml2 | < 6.5.0 |
Weakness: CWE-347 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
References
- https://github.com/IdentityPython/pysaml2/security/advisories/GHSA-5p3x-r448-pc62 x_refsource_CONFIRM
- https://pypi.org/project/pysaml2 x_refsource_MISC
- https://www.aleksey.com/pipermail/xmlsec/2013/009717.html x_refsource_MISC
- https://github.com/IdentityPython/pysaml2/releases/tag/v6.5.0 x_refsource_MISC
- https://github.com/IdentityPython/pysaml2/commit/46578df0695269a16f1c94171f1429873f90ed99 x_refsource_MISC
- [debian-lts-announce] 20210226 [SECURITY] [DLA 2577-1] python-pysaml2 security update mailing-list, x_refsource_MLIST