A PySAML2 security update is available for Ubuntu Linux 19.10, 19.04, 18.04 LTS, and 16.04 LTS to address a bypass signature verification with arbitrary data.

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Ubuntu Security Notice USN-4245-1
January 21, 2020

python-pysaml2 vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 19.10
- Ubuntu 19.04
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

PySAML2 could be made to bypass signature verification with arbitrary data.

Software Description:
- python-pysaml2: Pure python implementation of SAML2

Details:

It was discovered that PySAML2 incorrectly handled certain SAML files.
An attacker could possibly use this issue to bypass signature verification
with arbitrary data.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 19.10:
python-pysaml2 4.5.0+dfsg1-0ubuntu2.19.10.1
python3-pysaml2 4.5.0+dfsg1-0ubuntu2.19.10.1

Ubuntu 19.04:
python-pysaml2 4.5.0+dfsg1-0ubuntu2.19.04.1
python3-pysaml2 4.5.0+dfsg1-0ubuntu2.19.04.1

Ubuntu 18.04 LTS:
python-pysaml2 4.0.2-0ubuntu3.1
python3-pysaml2 4.0.2-0ubuntu3.1

Ubuntu 16.04 LTS:
python-pysaml2 3.0.0-3ubuntu1.16.04.4
python3-pysaml2 3.0.0-3ubuntu1.16.04.4

In general, a standard system update will make all the necessary changes.

References:
https://usn.ubuntu.com/4245-1
CVE-2020-5390

Package Information:
https://launchpad.net/ubuntu/+source/python-pysaml2/4.5.0+dfsg1-0ubuntu2.19.10.1
https://launchpad.net/ubuntu/+source/python-pysaml2/4.5.0+dfsg1-0ubuntu2.19.04.1
https://launchpad.net/ubuntu/+source/python-pysaml2/4.0.2-0ubuntu3.1
https://launchpad.net/ubuntu/+source/python-pysaml2/3.0.0-3ubuntu1.16.04.4