Authentication bypass between ZCC and client connector portal

published 2026-08-24 2 mo ago modified 2026-10-12 27 d ago also EUVD-2026-64860

cvss: 9.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits: 0; none known

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

Patch / fix

fixed in 1

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

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 2 mo ago (2026-08-24)

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	9.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

Zscaler Client Connector

Classification

Weakness

CWE-304 Missing Critical Step in Authentication

References

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

Sources

CVE List CVE-2026-59564
NVD CVE-2026-59564

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary