KeycloakApplication · Redhat
CVE-2020-10748
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's data filter, in version 10.0.1, where it allowed the processing of data URLs in some circumstances. This flaw allows an attacker to conduct cross-site scripting or further attacks.
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 confidenceIn Keycloak version 10.0.1, the data filter improperly allows processing of data URLs, enabling an attacker to inject malicious scripts that execute in the context of the victim's session. This cross-site scripting (XSS) vulnerability stems from insufficient validation of URL schemes in the data filtering mechanism.
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
= 10.0.1
Single Sign OnApplication
< 7.4.1CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/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 Keycloak versionCheck the Keycloak version by reviewing the server startup logs, the about page in the admin console, or the pom.xml/build files if you have access to the installation directory. On the server, you can also check the JAR manifest or version file in the Keycloak distribution.Affected if The installed version is exactly 10.0.1 for standalone Keycloak, or for Red Hat Single Sign-On the version is less than 7.4.1
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Locate data filter configurationSearch for data filter configuration files or XML descriptors in the Keycloak deployment. Look for files containing 'DataFilter' or 'dataFilter' in the conf, standalone, or domain configuration directories of your Keycloak installation.Affected if A data filter configuration exists and is enabled in the Keycloak configuration
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Test data URL processingIf you have access to an endpoint that utilizes the data filtering mechanism, attempt to submit a test request containing a data: URL scheme (for example: data:text/html,<script>alert(1)</script>) through the affected parameter or field.Affected if The system accepts and processes data: URLs without blocking or sanitizing them, allowing the URL to be stored or reflected back to users
You are affected if your Keycloak version is 10.0.1 or your Red Hat Single Sign-On version is below 7.4.1 AND the data filter component is enabled and processes data: URLs without validation.
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 data7.4.1
Upgrade Keycloak to version 10.0.2 or later where the data filter properly sanitizes or blocks data URLs. If immediate upgrade is not possible, implement additional input validation at the application layer to reject data: URLs.
Fix this in Keycloak
Scoped from the published advisory
- Consultation2.0 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 $4,480.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-10748 — 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-2020-10748 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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- Version or environment caveats, and links to real fixes
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