KeycloakApplication · Redhat
CVE-2023-0105
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 · uneditedA flaw was found in Keycloak. This flaw allows impersonation and lockout due to the email trust not being handled correctly in Keycloak. An attacker can shadow other users with the same email and lockout or impersonate them.
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 confidenceKeycloak fails to properly enforce email uniqueness across users, allowing an attacker to register or modify an account using an email address that already belongs to another user. This enables account impersonation or denial of service by locking legitimate users out of their accounts.
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
all versionsCVSS 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
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
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 checksWork through these to decide whether this CVE applies to you.
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Verify realm email uniqueness settingAccess Keycloak Admin Console, navigate to Realm Settings > Login, and check if 'Duplicate emails' is set to 'Permitted' or if there is an option to enforce unique email addresses that is disabledAffected if Email uniqueness is not enforced (the setting allows duplicate emails or the enforcement toggle is off)
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Query user database for duplicate emailsRun a database query to find users with duplicate email addresses, for example: SELECT email, COUNT(*) FROM user_entity WHERE email IS NOT NULL GROUP BY email HAVING COUNT(*) > 1Affected if Any results are returned showing multiple users share the same email address
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Check Keycloak versionUse 'bin/kc.sh --version' or check the server log at startup to determine the installed Keycloak versionAffected if Any version of Red Hat Keycloak is running (all versions are affected before proper configuration)
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Review authentication flow configurationNavigate to Authentication > Flows in Admin Console and verify if the 'Register' or 'Registration' flow has any email uniqueness validation configuredAffected if No email uniqueness validation step exists in the registration flow
A user is affected if email uniqueness is not enforced at the realm level OR duplicate email entries exist in the user database.
Generated from the published advisory. Verify against your own configuration.
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 dataConfigure Keycloak to enforce unique email addresses at the realm level and review existing user databases for duplicate email entries to remediate any existing shadowed accounts.
Fix this in Keycloak
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-0105 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-0105 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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