NVD / CVE Program· CNA redhat

CVE-2021-3636: It was found in OpenShift, before version 4.8, that the generated certificate for the in-cluster Service CA, incorrectly included additional

Noroxi assessment

Priority: Monitor (action score 18/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.28% (FIRST EPSS).
Someone on the same network segment can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 4.6 · v3.1—No exploit No fix recorded

Weak crypto

BDU:2021-03969

Published: Jul 30, 2021
Updated: Jun 17, 2026
EPSS: 0.2% · 21th percentile
CWE: CWE-295

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 18 / 40 · 4.6 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.2%

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Not in KEV: no record of exploitation in the wild
No public exploit code on record
No fixed version yet

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
redhat	openshift	cpe:2.3:a:redhat:openshift

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Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

redhat openshiftbefore 4.8

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

n/a openshift
- openshift 4.8affected

Same product

redhat: all records

Other highest-scoring records for the same primary product.

CVE-2014-3496cartridge_repository.rb in OpenShift Origin and Enterprise 1.2.8 through 2.1.1 allows remote attackers to execute arbitrary commands via she
42Plan
CVE-2013-2060The download_from_url function in OpenShift Origin allows remote attackers to execute arbitrary commands via shell metacharacters in the URL
41Plan
CVE-2014-0234The default configuration of broker.conf in Red Hat OpenShift Enterprise 2.x before 2.1 has a password of "mooo" for a Mongo account, which
40Plan

Published before and after this one in the same product

← EarlierCVE-2020-1761May 27, 2021 · A flaw was found in the OpenShift web console, where the access token is stored in the browser's local storage.
24Monitor
← EarlierCVE-2020-35514Jun 2, 2021 · An insecure modification flaw in the /etc/kubernetes/kubeconfig file was found in OpenShift.
28Monitor
Later →CVE-2021-4047Apr 11, 2022 · The release of OpenShift 4.9.6 included four CVE fixes for the haproxy package, however the patch for CVE-2021-39242 was missing.
30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

Someone on the same network segment can trigger it.
A low-privileged account is enough.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: low · data can be read
Integrity: low · data or configuration can be modified
Availability: none

Attack vector: Adjacent
Attack complexity: Low
Privileges required: Low
User interaction: None
Scope: Unchanged
Confidentiality impact: Low
Integrity impact: Low
Availability impact: None

Weakness class (CWE)

CWE-295 · Improper Certificate Validation

CVSS vector

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

nvd-primary

Root cause

A certificate validation error is silently swallowed instead of terminating the connection. Often, code added for a test environment makes its way into production.

The bug in code

The whole CWE-295 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

kotlin

1override fun checkServerTrusted(chain: Array<X509Certificate>, type: String) {
2  // Left empty for the test environment
3}

Fixed

kotlin

1val client = OkHttpClient.Builder()
2  .certificatePinner(
3    CertificatePinner.Builder()
4      .add("api.sirius.example", "sha256/…")
5      .build()
6  ).build()

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

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Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

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