CVE-2023-0264: A flaw was found in Keycloaks OpenID Connect user authentication, which may incorrectly authenticate requests

This month

MEDIUM 5.0WATCHLISTUPGRADEUPGRADEDOWNGRADE

CVE-2023-0264 is a medium-severity flaw (CVSS 5.0) affecting keycloak, single sign-on, openshift container platform. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A flaw was found in Keycloaks OpenID Connect user authentication, which may incorrectly authenticate requests. An authenticated attacker who could obtain information from a user request within the same realm could use that data to impersonate the victim and generate new session tokens. This issue could impact confidentiality, integrity, and availability.

Why this priority

On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	5.0 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.3% (top 30%)
CISA exploited list	No
Weakness	CWE-287
Published	2023-08-04
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: redhat

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-08-04 18:15 UTCPublished CVE record published
2026-06-17 05:25 UTCUpdated Record last modified

redhat keycloak UPGRADE

Affected: < 18.0.6

Fixed in: 18.0.6

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy keycloak || rpm -q keycloak || keycloak --version

2. UPGRADE to 18.0.6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade keycloak

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade keycloak

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

redhat single sign-on UPGRADE

Affected: < 7.6.2 · all versions

Fixed in: 7.6.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy single-sign-on || rpm -q single-sign-on || single-sign-on --version

2. UPGRADE to 7.6.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade single-sign-on

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade single-sign-on

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

redhat openshift container platform DOWNGRADE

Affected: 4.9 · 4.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.9

1. Check installed version

apt-cache policy openshift-container-platform || rpm -q openshift-container-platform || openshift-container-platform --version

2. No fixed release: DOWNGRADE to a release before 4.9 (Debian / Ubuntu)

apt-cache madison openshift-container-platform sudo apt install openshift-container-platform=<VERSION_BEFORE_4.9> sudo apt-mark hold openshift-container-platform

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openshift-container-platform sudo dnf downgrade openshift-container-platform-<VERSION_BEFORE_4.9> sudo dnf versionlock add openshift-container-platform

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

redhat openshift container platform for ibm linuxone DOWNGRADE

Affected: 4.9 · 4.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.9

1. Check installed version

apt-cache policy openshift-container-platform-for-ibm-linuxone || rpm -q openshift-container-platform-for-ibm-linuxone || openshift-container-platform-for-ibm-linuxone --version

2. No fixed release: DOWNGRADE to a release before 4.9 (Debian / Ubuntu)

apt-cache madison openshift-container-platform-for-ibm-linuxone sudo apt install openshift-container-platform-for-ibm-linuxone=<VERSION_BEFORE_4.9> sudo apt-mark hold openshift-container-platform-for-ibm-linuxone

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openshift-container-platform-for-ibm-linuxone sudo dnf downgrade openshift-container-platform-for-ibm-linuxone-<VERSION_BEFORE_4.9> sudo dnf versionlock add openshift-container-platform-for-ibm-linuxone

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

redhat openshift container platform ibm z systems DOWNGRADE

Affected: 4.9 · 4.10

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.9

1. Check installed version

apt-cache policy openshift-container-platform-ibm-z-systems || rpm -q openshift-container-platform-ibm-z-systems || openshift-container-platform-ibm-z-systems --version

2. No fixed release: DOWNGRADE to a release before 4.9 (Debian / Ubuntu)

apt-cache madison openshift-container-platform-ibm-z-systems sudo apt install openshift-container-platform-ibm-z-systems=<VERSION_BEFORE_4.9> sudo apt-mark hold openshift-container-platform-ibm-z-systems

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openshift-container-platform-ibm-z-systems sudo dnf downgrade openshift-container-platform-ibm-z-systems-<VERSION_BEFORE_4.9> sudo dnf versionlock add openshift-container-platform-ibm-z-systems

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-0264?

keycloak: upgrade to 18.0.6; single sign-on: upgrade to 7.6.2; openshift container platform: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-0264 being exploited?

CVE-2023-0264 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-0264 affect?

CVE-2023-0264 affects keycloak, single sign-on, openshift container platform. Severity is medium (CVSS 5.0). A flaw was found in Keycloaks OpenID Connect user authentication, which may incorrectly authenticate requests. An authenticated attacker who could obtain information from a user request within the same realm could use that data to impersona

How urgent is CVE-2023-0264?

Priority 40/100. On your watchlist

Software pages

Keycloak vulnerabilities · Red Hat OpenShift vulnerabilities

Related CVEs

CVE-2023-6927 MEDIUM 4.6 MITIGATE DOWNGRADE A flaw was found in Keycloak
CVE-2023-6563 HIGH 7.7 UPGRADE DOWNGRADE An unconstrained memory consumption vulnerability was discovered in Keycloak
CVE-2023-6291 HIGH 7.1 UPGRADE DOWNGRADE A flaw was found in the redirect_uri validation logic in Keycloak
CVE-2023-6134 MEDIUM 4.6 UPGRADE UPGRADE A flaw was found in Keycloak that prevents certain schemes in redirects, but permits them if a wildcard is app
CVE-2025-8419 MEDIUM 5.3 MITIGATE A vulnerability was found in Keycloak-services

References

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