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.
The record classifies CVE-2026-59564 under weakness class CWE-304. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 64 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 9.1 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - EPSS (FIRST)
- 0.5% probability of exploitation in the next 30 days, higher than 42.9% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 6.3/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-08-24, last modified 2026-08-25
Is CVE-2026-59564 being exploited?
It currently carries a trending score of 34 in the Threadlinqs vulnerability feed.
Affected products and versions
- Zscaler: Client Connector
How to fix CVE-2026-59564
No vendor patch reference has been recorded for CVE-2026-59564 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-59564
1 tracked threat in the Threadlinqs corpus references CVE-2026-59564, either in the campaign’s CVE list or as an indicator on the campaign record.
- Multiple Zscaler Client Connector Flaws Enable Remote Code Execution (CVE-2026-59568) — CRITICAL · 2026-08-25
Sources
Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on .