CVE-2021-3636

Name: CVE-2021-3636
Creator: NVD / NIST
Published: 2021-07-30T20:15:07.687+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.6/10EPSS 0.28%

Last modified Jun 17, 2026

CVE-2021-3636 is a medium-severity vulnerability rated 4.6/10 on the CVSS scale. It was found in OpenShift, before version 4.8, that the generated certificate for the in-cluster Service CA, incorrectly included additional certificates. The Service CA is automatically mounted into all pods, allowing them to safely connect to trusted in-cluster services that present certificates signed by the trusted Service CA. EPSS estimates a 0.28% chance of exploitation in the next 30 days.

Description

It was found in OpenShift, before version 4.8, that the generated certificate for the in-cluster Service CA, incorrectly included additional certificates. The Service CA is automatically mounted into all pods, allowing them to safely connect to trusted in-cluster services that present certificates signed by the trusted Service CA. The incorrect inclusion of additional CAs in this certificate would allow an attacker that compromises any of the additional CAs to masquerade as a trusted in-cluster service.

Metrics

CVSS 3.1

4.6/10

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

EPSS Probability

0.28%

20.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Redhat	Openshift	< 4.8

References

https://bugzilla.redhat.com/show_bug.cgi?id=1978621Exploit, Issue Tracking, Patch, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1978621Exploit, Issue Tracking, Patch, Third Party Advisory

Timeline

Published: Jul 30, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3636?

How severe is CVE-2021-3636?

CVE-2021-3636 has a CVSS score of 4.6/10 (MEDIUM severity). The EPSS model estimates a 0.28% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3636?

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.

Are you affected by CVE-2021-3636?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST