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SyncopeApplication · Apache

CVE-2026-23794

MEDIUM · 6.8 CVSS v3.1 Published 2026-02-03
Fix available
A fix is available. Upgrade to 3.0.16 / 4.0.4 or later.
See remediation →
72/100
Remediation priority · Elevated
Remotely reachable

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
Reflected XSS in Apache Syncope's Enduser Login page. An attacker that tricks a legitimate user into clicking a malicious link and logging in to Syncope Enduser could steal that user's credentials. This issue affects Apache Syncope: from 3.0 through 3.0.15, from 4.0 through 4.0.3. Users are recommended to upgrade to version 3.0.16 / 4.0.4, which fix this issue.

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 confidence

Reflected XSS vulnerability in Apache Syncope's Enduser Login page allows attackers to inject malicious scripts via URL parameters. When a user clicks a crafted link and logs in, the payload executes in the browser, enabling credential theft.

MitigationUpgrade to Apache Syncope version 3.0.16 or 4.0.4 which contain the fix; alternatively, implement output encoding and input validation on all login page parameters.

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
SyncopeApplication
Affected:>= 3.0.0, < 3.0.16>= 4.0.0, < 4.0.4

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
Low
Privileges
Low
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/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 checks

Work through these to decide whether this CVE applies to you.

  1. Determine installed Apache Syncope version
    Check the Syncope admin console under 'Configuration' > 'About', or inspect the WAR file metadata (MANIFEST.MF) in the deployed webapps directory, or search logs for startup version strings.
    Affected if The installed version falls within 3.0.0 to 3.0.15, or 4.0.0 to 4.0.3.
  2. Confirm enduser web application is deployed
    Verify the Syncope enduser UI is accessible by navigating to the enduser login endpoint (typically /syncope-enduser/ or /enduser/) and confirming the page loads.
    Affected if The enduser login page is publicly or internally accessible.
  3. Identify URL parameters on the login page
    Load the enduser login page and inspect all query parameters in the URL. Common parameters include 'redirect', 'from', 'lang', or 'token'. Use browser DevTools or a proxy to capture the full request URL.
    Affected if The login page accepts URL parameters that could be manipulated.
  4. Test for reflected parameter values
    Append a harmless test string (e.g., '?testparam=<script>alert(1)</script>') to the enduser login URL and observe whether the value appears unmodified in the rendered HTML page source.
    Affected if The test string appears verbatim in the page source without encoding or removal.
  5. Review any existing input filtering
    Examine any web application firewall (WAF) configurations, reverse proxy rules, or custom filters applied to the enduser endpoint. Check Syncope's 'Security' configuration section in the admin console for input validation settings.
    Affected if No input validation or output encoding is configured for login page parameters.

A user is affected if Apache Syncope version is between 3.0.0-3.0.15 or 4.0.0-4.0.3 AND the enduser login page accepts URL parameters that reflect unencoded values back into the page.

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.

dbcve · scoped
Upgrade available Upgrade to 3.0.16 / 4.0.4 or later
Fixed in 3.0.164.0.4
Interim mitigation

Upgrade to Apache Syncope version 3.0.16 or 4.0.4 which contain the fix; alternatively, implement output encoding and input validation on all login page parameters.

Recommended fix High confidence

3.0.16 (for 3.x branch) or 4.0.4 (for 4.x branch)

  1. 1. Identify your current Syncope version by checking the installed WAR file or pom.xml dependency
  2. 2. If running 3.0.x branch, plan upgrade to 3.0.16; if running 4.0.x branch, plan upgrade to 4.0.4
  3. 3. Back up your current Syncope installation including database, configuration files, and any custom extensions
  4. 4. Update the Syncope version in your build configuration (pom.xml) or download the new WAR from Apache Syncope releases
  5. 5. Deploy the new version to your test/staging environment first
  6. 6. Verify the Enduser login page loads correctly and basic authentication works
  7. 7. Deploy to production environment
  8. 8. Test that the reflected XSS vulnerability is no longer present by attempting to inject script tags in URL parameters
Caveat Patch releases typically contain only bug and security fixes with no breaking changes; review the release notes for any minor migration notes

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Syncope Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2026-23794 in production — separate from our analysis above.

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What this is

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.

What belongs here
  • 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