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CVE-2023-6563· NVD / CVE Program· CNA redhat

Keycloak: offline session token dos

Noroxi assessment

Priority: Monitor (action score 30/100)

  • 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: 1.2% (FIRST EPSS); higher than 68.9% of all records.
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: org.keycloak:keycloak-model-jpa (Maven) 21.0.0; rh-sso7-keycloak (Red Hat:red_hat_single_sign_on:7.6::el7) 0:18.0.11-2.redhat_00003.1.el7sso; rh-sso7-keycloak-server (Red Hat:red_hat_single_sign_on:7.6::el7) 0:18.0.11-2.redhat_00003.1.el7sso.

Low priority for now. Upgrade to org.keycloak:keycloak-model-jpa (Maven) 21.0.0; rh-sso7-keycloak (Red Hat:red_hat_single_sign_on:7.6::el7) 0:18.0.11-2.redhat_00003.1.el7sso; rh-sso7-keycloak-server (Red Hat:red_hat_single_sign_on:7.6::el7) 0:18.0.11-2.redhat_00003.1.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

An unconstrained memory consumption vulnerability was discovered in Keycloak. It can be triggered in environments which have millions of offline tokens (> 500,000 users with each having at least 2 saved sessions). If an attacker creates two or more user sessions and then open the "consents" tab of the admin User Interface, the UI attempts to load a huge number of offline client sessions leading to excessive memory and CPU consumption which could potentially crash the entire system.

HighCVSS 7.7 · v3.1—No exploit Fix available
Published
Dec 14, 2023
Updated
Sep 22, 2026
EPSS
1.2% · 68th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.7 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.2%

CNA vs NVD score

NVD
7.7
CNA · redhat
7.7
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

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

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2023-6563

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

VendorProduct
redhatkeycloak
redhatsingle sign-on
redhatenterprise linux
redhatopenshift container platform
redhatopenshift container platform for power
redhatopenshift container platform for ibm linuxone

Affected versions

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

  • redhat keycloakbefore 21.0.0
  • redhat openshift container platform4.11
  • redhat openshift container platform4.12
  • redhat openshift container platform for ibm linuxone4.10
  • redhat openshift container platform for ibm linuxone4.9
  • redhat openshift container platform for power4.10
  • redhat openshift container platform for power4.9
  • redhat single sign-onall versions
  • redhat single sign-on7.6

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.

  • Red Hat Red Hat Build of Keycloak

    • all versionsunknown

  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 7

    • 0:18.0.11-2.redhat_00003.1.el7sso and laternot affected · rpm

  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 8

    • 0:18.0.11-2.redhat_00003.1.el8sso and laternot affected · rpm

  • Red Hat Red Hat Single Sign-On 7.6 for RHEL 9

    • 0:18.0.11-2.redhat_00003.1.el9sso and laternot affected · rpm

  • Red Hat RHEL-8 based Middleware Containers

    • 7.6-38 and laternot affected · rpm
    • 7.6.6-2 and laternot affected · rpm

  • Red Hat Single Sign-On 7.6.6

    • all versionsunknown

Package-level exposure

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

EcosystemPackageAffected rangeFix
Mavenorg.keycloak:keycloak-model-jpabefore 21.0.021.0.0
Red Hat:red_hat_single_sign_on:7.6::el7rh-sso7-keycloakbefore 0:18.0.11-2.redhat_00003.1.el7sso0:18.0.11-2.redhat_00003.1.el7sso
Red Hat:red_hat_single_sign_on:7.6::el7rh-sso7-keycloak-serverbefore 0:18.0.11-2.redhat_00003.1.el7sso0:18.0.11-2.redhat_00003.1.el7sso
Red Hat:red_hat_single_sign_on:7.6::el8rh-sso7-keycloakbefore 0:18.0.11-2.redhat_00003.1.el8sso0:18.0.11-2.redhat_00003.1.el8sso
Red Hat:red_hat_single_sign_on:7.6::el8rh-sso7-keycloak-serverbefore 0:18.0.11-2.redhat_00003.1.el8sso0:18.0.11-2.redhat_00003.1.el8sso
Red Hat:red_hat_single_sign_on:7.6::el9rh-sso7-keycloakbefore 0:18.0.11-2.redhat_00003.1.el9sso0:18.0.11-2.redhat_00003.1.el9sso
Red Hat:red_hat_single_sign_on:7.6::el9rh-sso7-keycloak-serverbefore 0:18.0.11-2.redhat_00003.1.el9sso0:18.0.11-2.redhat_00003.1.el9sso

Same product

redhat: all records

Other highest-scoring records for the same primary product.

  • CVE-2020-10770A flaw was found in Keycloak before 13.0.0, where it is possible to force the server to call out an unverified URL using the OIDC parameter
    42Plan
  • CVE-2022-1245A privilege escalation flaw was found in the token exchange feature of keycloak.
    39Monitor
  • CVE-2019-14910A vulnerability was found in keycloak 7.x, when keycloak is configured with LDAP user federation and StartTLS is used instead of SSL/TLS fro
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2022-4137Sep 25, 2023 · Keycloak: reflected xss attack
    24Monitor
  • ← EarlierCVE-2023-2422Oct 4, 2023 · Keycloak: oauth client impersonation
    28Monitor
  • Later →CVE-2023-6927Dec 18, 2023 · Keycloak: open redirect via "form_post.jwt" jarm response mode
    24Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
Maven:org.keycloak:keycloak-model-jpa21.0.0Package registry (OSV)
red hat:rh-sso7-keycloak0:18.0.11-2.redhat_00003.1.el7sso · Red Hat:red_hat_single_sign_on:7.6::el7Package registry (OSV)
red hat:rh-sso7-keycloak-server0:18.0.11-2.redhat_00003.1.el7sso · Red Hat:red_hat_single_sign_on:7.6::el7Package 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.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted

Impact can extend beyond the vulnerable component (scope changes).

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-770 · Allocation of Resources Without Limits or Throttling

CVSS vector

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

nvd-primary

Attack context

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

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (6 more)

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

All records