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Build Of KeycloakApplication · Redhat

CVE-2026-4325

MEDIUM · 5.3 CVSS v3.1 Published 2026-04-02
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
60/100
Remediation priority · Elevated
Remotely reachable No privileges

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. The SingleUseObjectProvider, a global key-value store, lacks proper type and namespace isolation. This vulnerability allows an attacker to delete arbitrary single-use entries, which can enable the replay of consumed action tokens, such as password reset links. This could lead to unauthorized access or account compromise.

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 · moderate confidence

Keycloak's SingleUseObjectProvider, which serves as a global key-value store for single-use objects like consumed action tokens, lacks proper type and namespace isolation. This allows an authenticated or unauthenticated attacker to delete arbitrary single-use entries, enabling replay of consumed tokens such as password reset links. The vulnerability stems from the global nature of the storage without proper separation between different token types.

MitigationImplement proper namespace and type isolation in the SingleUseObjectProvider to ensure tokens cannot be manipulated across different contexts. Additionally, consider implementing immutable storage for consumed tokens or adding cryptographic verification to prevent token replay.

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
Build Of KeycloakApplication
Affected:all versions= 26.2= 26.2.15= 26.4= 26.4.11

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
High
Privileges
None
User interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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

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 Keycloak version
    Run 'kc.sh --version' or check the version from the Keycloak admin console under Server Info, or inspect the keycloak-server.jar metadata
    Affected if Running version 26.2, 26.2.15, 26.4, 26.4.11, or any version of Redhat Build Of Keycloak (all versions affected)
  2. Confirm SingleUseObjectProvider is in use
    Review Keycloak startup logs and verify that single-use token storage is active - check if action tokens (password reset, email verification, etc.) are being issued. Inspect the userSession or tokenPersister provider configuration in standalone.xml or standalone-ha.xml
    Affected if Keycloak is issuing single-use tokens (password reset, email verification, execute actions, etc.) and using the default SingleUseObjectProvider
  3. Check for namespace isolation in token storage
    Inspect the SingleUseObjectProvider implementation or configuration for namespace or type separation settings. Look for provider configuration under 'spi' section in Keycloak configuration files. Search for properties like 'namespace', 'typeIsolation', or 'isolation' in the single-use object provider setup
    Affected if No namespace or type isolation is configured - tokens of different types share a common global storage
  4. Verify token replay vulnerability exists
    Test by initiating a password reset, consuming the token, then attempting to query or delete the same entry via the SingleUseObjectProvider API without proper type checking. Check if the same entry key can be accessed across different token action types
    Affected if Single-use entries can be deleted or manipulated across different token types (e.g., deleting a consumed password reset token allows replay of that token)

A user is affected if they run any version of Redhat Build Of Keycloak (26.2, 26.2.15, 26.4, 26.4.11, or all versions) AND use Keycloak's single-use token features without proper namespace isolation configured for the SingleUseObjectProvider.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement proper namespace and type isolation in the SingleUseObjectProvider to ensure tokens cannot be manipulated across different contexts. Additionally, consider implementing immutable storage for consumed tokens or adding cryptographic verification to prevent token replay.

Fix this in Build Of Keycloak Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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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-2026-4325 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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