8.1

CVE-2026-25687: zscaler client_connector Race Condition within a Thread

CVSS: 8.1v3.1HighAwaiting analysis
Published 14-09-2026Last modified 15-09-2026
Open JSON

Vulnerability summary

CVE-2026-25687 is a high (CVSS 8.1) Race Condition within a Thread vulnerability in zscaler client_connector. EPSS estimates a 0.38% chance of exploitation in the next 30 days, higher than 30.5% of scored vulnerabilities.

Overall risk
32/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.1/10
010
High · v3.1 (CVE.org)
EPSS score
0.38%
0%100%
Low · +0.15 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 14-09-2026
    PublishedVulnerability first disclosed.
  2. 15-09-2026
    Last modifiedVulnerability information updated.

Description

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.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.38%

Chance of exploitation in the next 30 days

Percentile

31%

Versus all other CVEs

30-day change

+0.15 pp

From 0.23% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.38%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Zscaler1 product
  • client_connector≥ 4.6, < 4.6.0.486 | ≥ 4.7, < 4.7.0.350 | ≥ 4.8, < 4.8.0.267 | ≥ 4.9, < 4.9.0.412

1 vendor · 1 product

References

1 links