CVE-2026-59564

CRITICAL
Published Aug 24, 2026 Modified Aug 28, 2026 CWE-304

Description

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

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CVSS v3.1 Score

9.1
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS — Exploit Prediction

0.0030
Probability of exploitation
0.23%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-304 CWE-304

References

Frequently Asked Questions

What is CVE-2026-59564? +
An authentication bypass issue exists in communications between affected versions of the Zscaler Client Connector and the Zscaler Client Connector Portal. It has a CVSS v3.1 base score of 9.1 (CRITICAL).
How severe is CVE-2026-59564? +
CVE-2026-59564 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0030, placing it in the 0th percentile for exploitation probability.
How do I check if I'm vulnerable to CVE-2026-59564? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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