CVE-2023-20903: This disclosure regards a vulnerability related to UAA refresh tokens and external identity providers.Assuming that an external identity provider is l...

Description

This disclosure regards a vulnerability related to UAA refresh tokens and external identity providers.Assuming that an external identity provider is linked to the UAA, a refresh token is issued to a client on behalf of a user from that identity provider, the administrator of the UAA deactivates the identity provider from the UAA. It is expected that the UAA would reject a refresh token during a refresh token grant, but it does not (hence the vulnerability). It will continue to issue access tokens to request presenting such refresh tokens, as if the identity provider was still active. As a result, clients with refresh tokens issued through the deactivated identity provider would still have access to Cloud Foundry resources until their refresh token expires (which defaults to 30 days).

Metrics

CVSS 3.1

4.3/10

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS Probability

0.40%

32.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Cloudfoundry	User Account And Authentication	All versions

References

Timeline

Published: Mar 28, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-20903?

This disclosure regards a vulnerability related to UAA refresh tokens and external identity providers.Assuming that an external identity provider is linked to the UAA, a refresh token is issued to a client on behalf of a user from that identity provider, the administrator of the UAA deactivates the identity provider from the UAA. It is expected that the UAA would reject a refresh token during a refresh token grant, but it does not (hence the vulnerability). It will continue to issue access tokens to request presenting such refresh tokens, as if the identity provider was still active. As a result, clients with refresh tokens issued through the deactivated identity provider would still have access to Cloud Foundry resources until their refresh token expires (which defaults to 30 days).

How severe is CVE-2023-20903?

CVE-2023-20903 has a CVSS score of 4.3/10 (MEDIUM severity). The EPSS model estimates a 0.40% probability of exploitation in the next 30 days.

How do I fix CVE-2023-20903?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.