Cyber Resilience

CVE-2026-25687

Race Condition

Race Condition
Published
14 September 2026
Modified
18 September 2026
CVSS Score v3.1 8.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0023 14th percentile
Risk Priority 58 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-25687 is a high-severity Race Condition within a Thread (CWE-366) vulnerability in Zscaler Client Connector (inferred from references). Its CVSS base score is 8.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 14th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

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.

CWE(s)
CWE-366

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-58143Shared CWE-366
CVE-2024-10630Shared CWE-366
CVE-2023-3218Shared CWE-366
CVE-2026-22819Shared CWE-366
CVE-2026-3904Shared CWE-366
CVE-2026-46181Shared CWE-366
CVE-2023-4127Shared CWE-366
CVE-2023-4732Shared CWE-366
CVE-2024-6778Shared CWE-366
CVE-2026-23684Shared CWE-366

Affected Assets

Zscaler
Client Connector
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V15.4.2
  • V15.4.3
  • V17.2.6

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation partial match

Developer testing and evaluation can include concurrency and stress testing that finds race conditions after they have been coded.

SA-15 Development Process, Standards, and Tools partial match

Requiring documented development standards and tools can mandate use of safe concurrency patterns that avoid introducing races.

SA-8 Security and Privacy Engineering Principles partial match

Security engineering principles include requirements for synchronization primitives and thread-safe design that stop race conditions from being introduced.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 partial match
prevents

Secure SDLC practices directly require synchronization primitives and concurrency analysis that prevent intra-thread race conditions.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle includes concurrency and synchronization practices that reduce race conditions.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate thread-safety and locking controls.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles address concurrent access and resource synchronization.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly require proper synchronization primitives to prevent race conditions.

A.8.29 Security testing in development and acceptance partial match
finds

Security testing can detect race conditions through concurrency and stress testing.

References