CVE-2026-25687 PUBLISHED

ZCC race condition in ZPA tunnel handler

Assigner: Zscaler
Reserved: 05.02.2026 Published: 14.09.2026 Updated: 14.09.2026

A race condition in the ZPA tunnel handler of affected versions of Zscaler Client Connector (ZCC) allows a heap corruption, resulting in a denial of service (client crash) and potentially arbitrary code execution in the context of the ZCC process.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 8.1

Attack Vector	Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	High
Privileges Required	None	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	Zscaler
Product	Client Connector
Versions	Default: unaffected affected from 4.6 to 4.6.0.486 (excl.) affected from 4.7 to 4.7.0.350 (excl.) affected from 4.8 to 4.8.0.267 (excl.) affected from 4.9 to 4.9.0.412 (excl.)

Credits

GovTech Singapore Red Team finder

References

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

Problem Types

CWE-366 Race condition within a thread CWE

Impacts

CAPEC-549 Local Execution of Code