Vulnerability · Published Aug 24, 2026 · Assigned by Zscaler
CVE-2026-59564Authentication bypass between ZCC and client connector portal
Critical 9.1
In plain English
A critical-severity security flaw in Client Connector from Zscaler. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities).
Severity (CVSS 3.1)9.1Critical
Exploit odds (30 days)0.5%top 55.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
An authentication bypass issue exists in communications between affected versions of the Zscaler Client Connector and the Zscaler Client Connector Portal.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Zscaler | Client Connector | 0 – before Windows: 4.6.0.457, 4.7.0.317, 4.8.0.232, 4.9.0.3720 – before MacOS: 4.5.2.312, 4.7.0.292, 4.8.0.1910 – before iOS: 4.5.10 – before Android: 4.20 – before ChromeOS: 4.20 – before Linux: 3.7.2.64, 4.2.1.64 |
Weakness: CWE-304 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N