CVE-2020-26244 Cryptographic issues in Python oic
Attackers can bypass OpenID Connect authentication checks due to missing signature verification and algorithm validation in the Python oic library.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2020-26244?
CVE-2020-26244 is a medium-severity vulnerability in OpenIDC pyoidc, published on 2 Dec 2020. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Python oic is a Python OpenID Connect implementation. In Python oic before version 1.2.1, there are several related cryptographic issues affecting client implementations that use the library. The issues are: 1) The IdToken signature algorithm was not checked automatically, but only if the expected algorithm was passed in as a kwarg. 2) JWA `none` algorithm was allowed in all flows. 3) oic.consumer.Consumer.parse_authz returns an unverified IdToken. The verification of the token was left to the discretion of the implementator. 4) iat claim was not checked for sanity (i.e. it could be in the future). These issues are patched in version 1.2.1.
Which versions are affected by CVE-2020-26244?
3 open source packages ship an affected version, including oic. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
oic PyPI | All versions | 1.2.1 |
oic PyPI | All versions | 1.2.1 |
oic PyPI | All versions | 1.2.1 |
Linux distribution packages (2)
python-oic openSUSE:Tumbleweed | All versions | 1.5.0-1.8 |
python-oic openSUSE:Tumbleweed | All versions | 1.7.0-2.4 |
Products include Python Openid Connect Project Python Openid Connect.
How do I fix CVE-2020-26244?
Upgrade oic to 1.2.1 or later.
Is CVE-2020-26244 being exploited?
There is no known exploitation of CVE-2020-26244 in the wild and no public exploit code.
Sources
Also known as GHSA-4fjv-pmhg-3rfg, PYSEC-2020-69, openSUSE-SU-2024:11244-1, openSUSE-SU-2024:14150-1, openSUSE-SU-2026:12021-1.