CVE-2023-28800: Output encoding missing in redrurl parameter

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-06-22 · updated 2026-06-17
Weakness: CWE-79

Description

When using local accounts for administration, the redirect url parameter was not encoded correctly, allowing for an XSS attack providing admin login.

Affected products

Zscaler Client Connector: before 1.4; before 1.9.3; before 1.10.1; before 1.10.2; before 3.7; before 3.9 — fixed in 1.10.1, 1.10.2, 1.4, 1.9.3, 3.7, 3.9

How to fix

Upgrade to a fixed version: Zscaler Client Connector 1.10.1, 1.10.2, 1.4, 1.9.3. Check the vendor advisory for mitigations.

References

https://help.zscaler.com/client-connector/client-connector-app-release-summary-2022?applicable_category=Linux&applicable_version=1.4&deployment_date=2022-10-31&id=1420246
https://help.zscaler.com/client-connector/client-connector-app-release-summary-2023?applicable_category=Android&applicable_version=1.10.2&deployment_date=2023-03-09&id=1447706
https://help.zscaler.com/client-connector/client-connector-app-release-summary-2023?applicable_category=Chrome%20OS&applicable_version=1.10.1&deployment_date=2023-03-10&id=1447771
https://help.zscaler.com/client-connector/client-connector-app-release-summary-2023?applicable_category=iOS&applicable_version=1.9.3&deployment_date=2023-03-03&id=1447071
https://help.zscaler.com/client-connector/client-connector-app-release-summary-2023?applicable_category=macOS&applicable_version=3.9&deployment_date=2023-01-25&id=1443546
https://help.zscaler.com/zscaler-client-connector/client-connector-app-release-summary-2021?applicable_category=Windows&applicable_version=3.7&deployment_date=2021-11-26&id=1386541
https://help.zscaler.com/client-connector/client-connector-app-release-summary-2022?applicable_category=Linux&applicable_version=1.4&deployment_date=2022-10-31&id=1420246
https://help.zscaler.com/client-connector/client-connector-app-release-summary-2023?applicable_category=Android&applicable_version=1.10.2&deployment_date=2023-03-09&id=1447706
https://help.zscaler.com/client-connector/client-connector-app-release-summary-2023?applicable_category=Chrome%20OS&applicable_version=1.10.1&deployment_date=2023-03-10&id=1447771
https://help.zscaler.com/client-connector/client-connector-app-release-summary-2023?applicable_category=iOS&applicable_version=1.9.3&deployment_date=2023-03-03&id=1447071
https://help.zscaler.com/client-connector/client-connector-app-release-summary-2023?applicable_category=macOS&applicable_version=3.9&deployment_date=2023-01-25&id=1443546
https://help.zscaler.com/zscaler-client-connector/client-connector-app-release-summary-2021?applicable_category=Windows&applicable_version=3.7&deployment_date=2021-11-26&id=1386541

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