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Full vulnerability report · 2023
CVE-2023-1664High confidence

A flaw was found in Keycloak

n/a · Keycloak

6.5MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2023-1664 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitykeycloak: Untrusted Certificate Validation
4 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • org.keycloak-keycloak-core.src as a component of Migration Toolkit for Runtimes
  • keycloak-core as a component of Red Hat build of Apicurio Registry 2
  • keycloak-core as a component of Red Hat build of Quarkus
  • keycloak-core as a component of Red Hat Fuse 7
Summary
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, but consumer applications Integrity or Confidentiality. Considering the environment is correctly set, this flaw is avoidable by configuring the server.
Remediation
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2023-1697

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

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.

What

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.

Why

The product does not validate, or incorrectly validates, a certificate.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The product does not validate, or incorrectly validates, a certificate.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Certificate Validation → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-295 ↗

CWE-295: Improper Certificate Validation. The product does not validate, or incorrectly validates, a certificate.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-295
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-W-2023-0764Keycloak: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Keycloak und Red Hat Single Sign On ausnutzen, um Sicherheitsvorkehrungen zu umgehen.

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
org.keycloak-keycloak-core.src as a component of Migration Toolkit for Runtimes; keycloak-core as a component of Red Hat build of Apicurio Registry 2; keycloak-core as a component of Red Hat build of Quarkus; keycloak-core as a component of Red Hat Fuse 7
Fixed
rh-sso7-keycloak-0:18.0.8-1.redhat_00001.1.el7sso.noarch as a component of Red Hat Single Sign-On 7.6 for RHEL 7 Server; rh-sso7-keycloak-0:18.0.8-1.redhat_00001.1.el7sso.src as a component of Red Hat Single Sign-On 7.6 for RHEL 7 Server; rh-sso7-keycloak-server-0:18.0.8-1.redhat_00001.1.el7sso.noarch as a component of Red Hat Single Sign-On 7.6 for RHEL 7 Server; rh-sso-7/sso76-openshift-rhel8@sha256:b8452b9ca79791555bb4709a4d3c81768e0571f72fe88480be9dfd585e02913e_s390x as a component of Middleware Containers for OpenShift; rh-sso-7/sso76-openshift-rhel8@sha256:d15acb2c2c6bed9934c011c6864ca5c2ae989f783390bdb3eca77f5fc4ccc92a_amd64 as a component of Middleware Containers for OpenShift; rh-sso-7/sso76-openshift-rhel8@sha256:f52cb785c11ab691e0583a69e665496af83b4191037742ef2b1dd1237f42722e_ppc64le as a component of Middleware Containers for OpenShift; rh-sso7-keycloak-0:18.0.8-1.redhat_00001.1.el8sso.noarch as a component of Red Hat Single Sign-On 7.6 for RHEL 8; rh-sso7-keycloak-0:18.0.8-1.redhat_00001.1.el8sso.src as a component of Red Hat Single Sign-On 7.6 for RHEL 8; rh-sso7-keycloak-server-0:18.0.8-1.redhat_00001.1.el8sso.noarch as a component of Red Hat Single Sign-On 7.6 for RHEL 8; rh-sso7-keycloak-0:18.0.8-1.redhat_00001.1.el9sso.noarch as a component of Red Hat Single Sign-On 7.6 for RHEL 9; rh-sso7-keycloak-0:18.0.8-1.redhat_00001.1.el9sso.src as a component of Red Hat Single Sign-On 7.6 for RHEL 9; rh-sso7-keycloak-server-0:18.0.8-1.redhat_00001.1.el9sso.noarch as a component of Red Hat Single Sign-On 7.6 for RHEL 9; AMQ Broker 7.11.2; Red Hat Single Sign-On 7
Action
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 26 May 2023 · Last source change 15 Jan 2025, 21:34 UTC · CWE-295 · Improper Certificate Validation

CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2023-1697
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2023-1697↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2023-1664 · cve.blacktree.nl