# CVE-2026-59566 — Zscaler Client Connector

> As of 2026-08-24, CVE-2026-59566 is a HIGH-severity vulnerability in Zscaler Client Connector, CVSS v3.1 8.4, EPSS 0.1% (6.4th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-59566, most recently “Multiple Zscaler Client Connector Flaws Enable Remote Code Execution (CVE-2026-59568)”.

**Last updated:** 2026-08-24

## What is CVE-2026-59566?

A locally exploitable buffer overflow bug can cause a local denial-of-service attack on affected versions of Zscaler Client Connector on Android and ChromeOS.

The record classifies CVE-2026-59566 under weakness class [CWE-229](https://cwe.mitre.org/data/definitions/229.html). Its CVSS v3 base vector states that the flaw requires local access to the host, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 65 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 8.4 — HIGH (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **EPSS (FIRST):** 0.1% probability of exploitation in the next 30 days, higher than 6.4% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 4.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-08-24

## Is CVE-2026-59566 being exploited?

It currently carries a trending score of 25 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [Zscaler](https://intel.threadlinqs.com/vendors/zscaler): Client Connector

## How to fix CVE-2026-59566

No vendor patch reference has been recorded for CVE-2026-59566 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-2026-59566

1 tracked threat in the Threadlinqs corpus references CVE-2026-59566, 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)](https://intel.threadlinqs.com/threat/TL-2026-2139) — CRITICAL · 2026-08-25

## Sources

Enriched from CVE.org, FIRST EPSS. Last verified by Threadlinqs on 2026-10-10.

**Other references**

- [help.zscaler.com](https://help.zscaler.com/zscaler-client-connector/client-connector-app-release-summary-2026)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-59566
Full detection coverage and IOCs for threats exploiting CVE-2026-59566 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp