ZCC race condition in ZPA tunnel handler

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-25687
StatePUBLISHED
AssignerZscaler
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-14 15:17:05 UTC
Updated2026-09-18 19:08:02 UTC
DescriptionA 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.

Risk And Classification

Primary CVSS: v3.1 8.1 HIGH from [email protected]

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

EPSS: 0.002310000 probability, percentile 0.142490000 (date 2026-09-21)

Problem Types: CWE-366 | CWE-366 CWE-366 Race condition within a thread

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary8.1HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNACVSS8.1HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Zscaler Client Connector affected 4.6 4.6.0.486 custom Windows
CNA Zscaler Client Connector affected 4.7 4.7.0.350 custom Windows
CNA Zscaler Client Connector affected 4.8 4.8.0.267 custom Windows
CNA Zscaler Client Connector affected 4.9 4.9.0.412 custom Windows

References

ReferenceSourceLinkTags
help.zscaler.com/zscaler-client-connector/client-connector-app-release-summary... [email protected] help.zscaler.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: GovTech Singapore Red Team (en)

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