Client ConnectorApplication · Zscaler
CVE-2023-28800
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 · uneditedWhen using local accounts for administration, the redirect url parameter was not encoded correctly, allowing for an XSS attack providing admin login.
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 confidenceThis is a reflected Cross-Site Scripting (XSS) vulnerability in the redirect URL parameter when local accounts are used for administration. The application fails to properly encode/sanitize the redirect URL parameter before including it in the response, allowing an attacker to inject malicious JavaScript code that executes in the victim's browser when navigating to the crafted URL.
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
Client ConnectorApplication
< 1.4< 1.9.3< 1.10.1< 1.10.2< 3.7< 3.9CVSS 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 if Zscaler Client Connector is installedCheck for the presence of Zscaler Client Connector on the system. On Windows, look for the application in Add/Remove Programs or check Program Files for 'Zscaler' folder. On macOS, check /Applications for 'Zscaler Client Connector' or use 'ls /Applications | grep -i zscaler'.Affected if The application is not found on the system.
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Determine the installed version of Zscaler Client ConnectorOn Windows, open the Control Panel > Programs and Features, find 'Zscaler Client Connector' and note the version column. Alternatively, right-click the Zscaler icon in the system tray and select 'About' or use 'Get-ItemProperty' in PowerShell for registry keys under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\ or HKLM\SOFTWARE\Zscaler. On macOS, right-click the app in Applications and select 'Get Info' or use the command 'defaults read /Applications/Zscaler\ Client\ Connector.app/Contents/Info CFBundleShortVersionString'.Affected if The installed version matches any of these ranges: < 1.4, < 1.9.3, < 1.10.1, < 1.10.2, < 3.7, or < 3.9.
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Verify if local accounts are used for administrationCheck the Zscaler Client Connector admin settings or documentation to determine whether local user accounts (as opposed to SSO/SSO-enabled directory accounts) are being used for administrative access to the client connector. This may require logging into the admin interface or checking configuration files if accessible.Affected if Local user accounts are configured for administration of the Zscaler Client Connector.
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Inspect redirect URL parameter handlingIf the product is installed and vulnerable version identified, examine HTTP requests/responses when accessing the admin interface with a redirect parameter. In a test environment, navigate to the admin login page with a crafted URL such as 'https://admininterface/login?redirect=<script>alert(1)</script>' and observe if the script executes in the response without encoding.Affected if The redirect parameter value is reflected in the response without proper HTML encoding.
A user is affected if Zscaler Client Connector is installed with a version in any of the affected ranges AND local admin accounts are being used, allowing the reflected XSS to trigger via the unencoded redirect URL parameter.
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 · scoped1.41.9.31.10.1
Implement proper output encoding for the redirect URL parameter before rendering it in HTML context. Additionally, implement input validation to ensure the redirect URL points to expected domains or paths, and consider using a whitelist approach for allowed redirect destinations.
Zscaler Client Connector 1.10.2 or later (or 1.9.3+, or 1.4+ depending on your branch)
- Identify the current installed version of Zscaler Client Connector
- Access the Zscaler admin portal or use the built-in update mechanism
- Navigate to the Client Connector settings or administration section
- Check for available updates and initiate the upgrade process
- Verify the upgrade completes successfully
- Confirm the new version is at least 1.10.2 or later
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Client Connector
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 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 $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-28800 — 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-2023-28800 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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