Critical severity · published Aug 24, 2026
CVE-2026-59564
Authentication bypass between ZCC and client connector portal
9.1
CVSS
0.5%
EPSS
No
On KEV
Description
An authentication bypass issue exists in communications between affected versions of the Zscaler Client Connector and the Zscaler Client Connector Portal.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 45% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CC
Client Connector · Zscaler
before Windows: 4.6.0.457, 4.7.0.317, 4.8.0.232, 4.9.0.372; before MacOS: 4.5.2.312, 4.7.0.292, 4.8.0.191; before iOS: 4.5.1; before Android: 4.2; before ChromeOS: 4.2; before Linux: 3.7.2.64, 4.2.1.64 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-59564
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-59564
help.zscaler.com
https://help.zscaler.com/zscaler-client-connector/client-connector-app-release-summary-2026
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