KeycloakApplication · Redhat
CVE-2021-3513
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 where a brute force attack is possible even when the permanent lockout feature is enabled. This is due to a wrong error message displayed when wrong credentials are entered. The highest threat from this vulnerability is to confidentiality.
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's permanent account lockout feature can be bypassed due to an incorrect error message being displayed during authentication failures. This allows attackers to perform unlimited brute force password guessing even on accounts that should be permanently locked out, primarily impacting confidentiality through unauthorized access.
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
< 13.0.0CVSS 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
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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 checksWork through these to decide whether this CVE applies to you.
-
Check installed Keycloak versionRun 'kc.sh --version' or check the Keycloak server startup logs for the version numberAffected if The installed version is Redhat Keycloak below version 13.0.0
-
Verify permanent lockout is configuredAccess Keycloak admin console, navigate to Authentication > Password Policy, and check if a permanent lockout (brute force) policy is enabledAffected if Permanent account lockout policy is set for user accounts
-
Test authentication failure error messagesAttempt multiple failed login attempts on a permanently locked account and observe the error message returnedAffected if The error message does not clearly indicate the account is permanently locked, or allows further authentication attempts to proceed
-
Check brute force protection statusReview authentication flow configurations in Keycloak for any brute force or account lockout failure countersAffected if Brute force protection appears to not be enforcing permanent lockout as expected or error handling differs from expected behavior
A user is affected if they are running Redhat Keycloak below version 13.0.0 with permanent lockout enabled, and the authentication failure response allows unlimited password guessing attempts.
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.
dbcve · scoped13.0.0
Apply Keycloak security patches for this vulnerability, and consider implementing additional controls like CAPTCHA, rate limiting at the proxy level, or enabling multi-factor authentication as compensating controls until the patch is deployed.
Keycloak 13.0.0
- Upgrade Keycloak to version 13.0.0 or later to resolve the brute force protection bypass vulnerability
- After upgrade, verify that the permanent lockout feature is functioning correctly by testing with incorrect credentials
- Confirm that proper error messages are displayed when permanent lockout is triggered, ensuring no information leakage that could aid brute force attacks
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Keycloak
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-3513 — 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-2021-3513 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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