by Kastro
Paper/Archive/CVE-2026-59564

CVE-2026-59564

Zscaler Client Connector — Authentication bypass between ZCC and client connector portal

EPSS 0.5%CVSS 9.1
critical.is priorityof 100
36
CVSS 9.1 (CNA)9.1 / 10 × 3027.3Not in CISA KEV+300.0EPSS percentile 44.8.448 × 209.0No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

An authentication bypass issue exists in communications between affected versions of the Zscaler Client Connector and the Zscaler Client Connector Portal.

Affected

ProductAffectedFixed inSource
Client Connector< Windows: 4.6.0.457, 4.7.0.317, 4.8.0.232, 4.9.0.372Windows: 4.6.0.457, 4.7.0.317, 4.8.0.232, 4.9.0.372CNA
Client Connector< MacOS: 4.5.2.312, 4.7.0.292, 4.8.0.191MacOS: 4.5.2.312, 4.7.0.292, 4.8.0.191CNA
Client Connector< iOS: 4.5.1iOS: 4.5.1CNA
Client Connector< Android: 4.2Android: 4.2CNA
Client Connector< ChromeOS: 4.2ChromeOS: 4.2CNA
Client Connector< Linux: 3.7.2.64, 4.2.1.64Linux: 3.7.2.64, 4.2.1.64CNA

Scores by source

Zscaler (CNA)9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refhelp.zscaler.com/zscaler-client-connector/client-connector-app-release-summary-2026