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KeycloakApplication · Redhat

CVE-2021-3637

HIGH · 7.5 CVSS v3.1 Published 2021-07-09
Fix available
A fix is available. Upgrade to 14.0.0 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A flaw was found in keycloak-model-infinispan in keycloak versions before 14.0.0 where authenticationSessions map in RootAuthenticationSessionEntity grows boundlessly which could lead to a DoS attack.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In Keycloak versions before 14.0.0, the keycloak-model-infinispan component contains a vulnerability where the authenticationSessions map in RootAuthenticationSessionEntity grows without bound. This unbounded growth can lead to memory exhaustion and result in a denial of service condition.

MitigationUpgrade Keycloak to version 14.0.0 or later to receive the fix for the unbounded authenticationSessions map growth.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
KeycloakApplication
Affected:< 14.0.0
Single Sign OnApplication
Affected:= 7.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed Keycloak version
    Run the version check command provided by Keycloak, typically found in the bin directory (such as bin/jboss-cli.sh or checking the server startup logs), or inspect the manifest/pom files in the Keycloak installation directory
    Affected if The version is less than 14.0.0 for Red Hat Keycloak or equals 7.0 for Red Hat Single Sign-On
  2. Confirm the keycloak-model-infinispan component is in use
    Check the Keycloak installation for the presence of the infinispan model module (keycloak-model-infinispan jar or module), which is typically included in the server distribution under the modules directory
    Affected if The infinispan model component is present in the deployment, which is the default configuration in standard Keycloak installations
  3. Verify authentication session handling is enabled
    Inspect the Keycloak configuration to confirm that authentication sessions are being stored. This is typically enabled by default in standard Keycloak deployments using the Infinispan session cache. Check the standalone.xml or standalone-ha.xml configuration files for the authenticationSessions cache configuration
    Affected if Authentication sessions are configured to use Infinispan caching (the default behavior in standard installations)
  4. Check for memory growth indicators
    Monitor JVM memory usage over time, particularly the heap allocated to the Infinispan cache that stores authenticationSessions. Review server logs and metrics for OutOfMemoryError events or steadily increasing memory consumption related to session storage
    Affected if Memory usage grows unbounded over time with active user authentication sessions, indicating the unbounded map issue is manifesting

You are affected if you are running Red Hat Keycloak versions before 14.0.0 or Red Hat Single Sign-On version 7.0 with the default Infinispan-based authentication session handling enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 14.0.0 or later
Fixed in 14.0.0
Interim mitigation

Upgrade Keycloak to version 14.0.0 or later to receive the fix for the unbounded authenticationSessions map growth.

Fix this in Keycloak Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,888.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-3637 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data