Build Of KeycloakApplication · Redhat
CVE-2026-7571
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. A low-privilege user, with knowledge of user credentials and client ID, can bypass a security control intended to disable the implicit flow in OpenID Connect (OIDC) clients. By manipulating client data during a session restart, an attacker can obtain an access token that should not be available. This vulnerability can also lead to the exposure of these access tokens in server logs, proxy logs, and HTTP Referrer headers, resulting in sensitive information disclosure.
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 confidenceKeycloak contains a security control bypass where low-privilege users with valid credentials and client ID can circumvent the implicit flow disablement by manipulating client data during session restart, allowing unauthorized access token acquisition. The obtained tokens may then be exposed through server logs, proxy logs, and HTTP Referrer headers.
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
>= 26.4, < 26.4.12CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/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.
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Identify installed Keycloak versionRun the Keycloak version command (bin/kc.sh --version) or check the RPM/package version (rpm -q or dpkg -l)Affected if The installed version is >= 26.4 and < 26.4.12
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Verify client implicit flow configurationReview OIDC client settings in the Keycloak admin console or client configuration files to confirm whether implicit flow is intended to be disabledAffected if Implicit flow is disabled in client configuration but the vulnerability may still apply due to the bypass mechanism
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Examine Keycloak server logs for exposed tokensSearch Keycloak server log files for access token strings (typically JWT format beginning with 'eyJ') that may have been logged during authentication flowsAffected if Access tokens appear in server logs, indicating token exposure
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Check reverse proxy/access logs for token leakageInspect reverse proxy (e.g., nginx, httpd) or load balancer logs for JWT tokens in request paths, headers, or query parametersAffected if JWT access tokens are visible in proxy or access logs
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Review HTTP Referrer header dataExamine application or CDN logs for Referrer headers that may contain access tokens in URLs being passed to third-party sitesAffected if Access tokens are being transmitted in HTTP Referrer headers to external domains
You are affected if running a Red Hat Build of Keycloak version 26.4 through 26.4.11 and tokens are found exposed in any logs or Referrer headers.
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 · scoped26.4.12
Review and properly enforce OIDC client configuration to ensure implicit flow is disabled, audit all logs for token exposure, and rotate any potentially compromised credentials or tokens.
26.4.12
- Upgrade Keycloak to version 26.4.12 or later to remediate this vulnerability
- After upgrading, verify that the implicit flow is properly disabled for affected OIDC clients
- Review server logs, proxy logs, and HTTP access logs to check for any leaked access tokens that may have been generated during exploitation
- If tokens were exposed, rotate the affected access tokens and consider revoking active sessions
- Ensure client configurations for OIDC explicitly disable implicit flow if not needed
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Build Of Keycloak
Scoped from the published advisory
- Consultation6.0 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 $5,760.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-7571 — 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-2026-7571 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
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