NVD / CVE Program· CNA redhat

CVE-2023-1664: A flaw was found in Keycloak.

Noroxi assessment

Priority: Monitor (action score 26/100)

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: 0.42% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: org.keycloak:keycloak-core (Maven) 21.1.2; rh-sso7-keycloak (Red Hat:red_hat_single_sign_on:7.6::el7) 0:18.0.8-1.redhat_00001.1.el7sso; rh-sso7-keycloak-server (Red Hat:red_hat_single_sign_on:7.6::el7) 0:18.0.8-1.redhat_00001.1.el7sso.

Low priority for now. Upgrade to org.keycloak:keycloak-core (Maven) 21.1.2; rh-sso7-keycloak (Red Hat:red_hat_single_sign_on:7.6::el7) 0:18.0.8-1.redhat_00001.1.el7sso; rh-sso7-keycloak-server (Red Hat:red_hat_single_sign_on:7.6::el7) 0:18.0.8-1.redhat_00001.1.el7sso or later.

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

A flaw was found in Keycloak. This flaw depends on a non-default configuration "Revalidate Client Certificate" to be enabled and the reverse proxy is not validating the certificate before Keycloak. Using this method an attacker may choose the certificate which will be validated by the server. If this happens and the KC_SPI_TRUSTSTORE_FILE_FILE variable is missing/misconfigured, any trustfile may be accepted with the logging information of "Cannot validate client certificate trust: Truststore not available". This may not impact availability as the attacker would have no access to the server, but consumer applications Integrity or Confidentiality may be impacted considering a possible access to them. Considering the environment is correctly set to use "Revalidate Client Certificate" this flaw is avoidable.

MediumCVSS 6.5 · v3.1—No exploit Fix available

Published: May 26, 2023
Updated: Jun 17, 2026
EPSS: 0.4% · 35th percentile
CWE: CWE-295

Report tools

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Action score

Monitor

Low priority for now.

CVSS: 26 / 40 · 6.5 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.4%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

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Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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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	build of quarkus	cpe:2.3:a:redhat:build_of_quarkus
redhat	jboss a-mq	cpe:2.3:a:redhat:jboss_a-mq
redhat	keycloak	cpe:2.3:a:redhat:keycloak
redhat	migration toolkit for runtimes	cpe:2.3:a:redhat:migration_toolkit_for_runtimes
redhat	single sign-on	cpe:2.3:a:redhat:single_sign-on

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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 build of quarkusall versions
redhat jboss a-mq7
redhat keycloakall versions
redhat migration toolkit for runtimesall versions
redhat single sign-on7.0

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 Keycloak
- NAaffected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Maven	org.keycloak:keycloak-core	before 21.1.2	21.1.2
Red Hat:red_hat_single_sign_on:7.6::el7	rh-sso7-keycloak	before 0:18.0.8-1.redhat_00001.1.el7sso	0:18.0.8-1.redhat_00001.1.el7sso
Red Hat:red_hat_single_sign_on:7.6::el7	rh-sso7-keycloak-server	before 0:18.0.8-1.redhat_00001.1.el7sso	0:18.0.8-1.redhat_00001.1.el7sso
Red Hat:red_hat_single_sign_on:7.6::el8	rh-sso7-keycloak	before 0:18.0.8-1.redhat_00001.1.el8sso	0:18.0.8-1.redhat_00001.1.el8sso
Red Hat:red_hat_single_sign_on:7.6::el8	rh-sso7-keycloak-server	before 0:18.0.8-1.redhat_00001.1.el8sso	0:18.0.8-1.redhat_00001.1.el8sso
Red Hat:red_hat_single_sign_on:7.6::el9	rh-sso7-keycloak	before 0:18.0.8-1.redhat_00001.1.el9sso	0:18.0.8-1.redhat_00001.1.el9sso
Red Hat:red_hat_single_sign_on:7.6::el9	rh-sso7-keycloak-server	before 0:18.0.8-1.redhat_00001.1.el9sso	0:18.0.8-1.redhat_00001.1.el9sso

Same product

redhat: all records

Other highest-scoring records for the same primary product.

CVE-2023-2974Quarkus-core: tls protocol configured with quarkus.http.ssl.protocols is not enforced, client can enforce weaker supported tls protocol
32Monitor
CVE-2023-1108Undertow: infinite loop in sslconduit during close
31Monitor
CVE-2022-4492The undertow client is not checking the server identity presented by the server certificate in https connections.
30Monitor

Published before and after this one in the same product

← EarlierCVE-2021-3914Aug 25, 2022 · It was found that the smallrye health metrics UI component did not properly sanitize some user inputs.
24Monitor
← EarlierCVE-2022-1259Aug 31, 2022 · A flaw was found in Undertow.
30Monitor
Later →CVE-2023-6393Dec 6, 2023 · Quarkus: potential invalid reuse of context when @cacheresult on a uni is used
21Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
Maven:org.keycloak:keycloak-core	21.1.2	Package registry (OSV)
red hat:rh-sso7-keycloak	0:18.0.8-1.redhat_00001.1.el7sso · Red Hat:red_hat_single_sign_on:7.6::el7	Package registry (OSV)
red hat:rh-sso7-keycloak-server	0:18.0.8-1.redhat_00001.1.el7sso · Red Hat:red_hat_single_sign_on:7.6::el7	Package registry (OSV)

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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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

Anyone who can reach it over the internet can trigger it.
No account or password is required.
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: Network
Attack complexity: Low
Privileges required: None
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:N/AC:L/PR:N/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

—

Change log

Fix✗ → ✓Sep 28, 2026, 10:44 PM UTC

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References

bugzilla.redhat.com/show_bug.cgi?id=2182196&comment#0

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records