# CVE-2026-59566: Zscaler Client Connector buffer overflow on Android and ChromeOS

Source: https://junglewise.ai/threats/cve-2026-59566-zscaler-client-connector-buffer-overflow-on-android-and-chromeos  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-24. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-59566 · Severity: high · CVSS 8.4 · Published 2026-08-24

Zscaler Client Connector is a security client used to protect mobile and chromebook devices by securely routing traffic through Zscaler's cloud security platform. A buffer overflow flaw in the application can be exploited by a local attacker to crash the application, disrupting the user's network security protection and potentially leaving the device vulnerable during the outage.

Technologies: [Zscaler Client Connector](https://junglewise.ai/threats/technologies/client-connector). Vendors: [Zscaler](https://junglewise.ai/threats/vendors/zscaler).

## Quick answers

**Is CVE-2026-59566 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-59566 being exploited in the wild.

**How severe is CVE-2026-59566?** High severity, with a CVSS score of 8.4, published 24 August 2026.

**Which products and versions are affected?** Zscaler Client Connector <UNKNOWN>.

**Is there a fix for CVE-2026-59566?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-59566 attacked?** It is attacked with local access, in a network appliance.

**Am I affected by CVE-2026-59566?** Check whether you run Zscaler Client Connector at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A locally exploitable buffer overflow vulnerability exists in Zscaler Client Connector on Android and ChromeOS platforms. The vulnerability allows a local attacker with access to the affected device to trigger the buffer overflow through a malformed input, causing the application to crash and resulting in a denial-of-service condition. No network access or authentication is required for exploitation. The attack impacts availability by preventing the security client from operating, removing the device's connection to Zscaler's security services. Patches are expected to be available in updated releases of Client Connector.

## Affected products

- Zscaler Client Connector <UNKNOWN>

## Timeline

- 2026-08-24: disclosed

## References

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

## Related threats

- [Zscaler Client Connector peer app access control bypass](https://junglewise.ai/threats/cve-2026-59570-zscaler-client-connector-peer-app-access-control-bypass)
- [Zscaler Client Connector improper input validation on Android and ChromeOS](https://junglewise.ai/threats/cve-2026-59569-zscaler-client-connector-improper-input-validation-on-android-and)
- [Zscaler Client Connector race condition in ZPA tunnel handler](https://junglewise.ai/threats/cve-2026-25687-zscaler-client-connector-race-condition-in-zpa-tunnel-handler)
- [Zscaler Client Connector remote code execution](https://junglewise.ai/threats/cve-2026-59568-zscaler-client-connector-remote-code-execution)
- [Zscaler Client Connector local privilege escalation](https://junglewise.ai/threats/cve-2026-59567-zscaler-client-connector-local-privilege-escalation)