How severe is CVE-2021-26734?

CVE-2021-26734 has a CVSS 3.x base score of 4.4, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-26734 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26734?

CVE-2021-26734 affects Zscaler Client Connector. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-26734?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-26734 published?

CVE-2021-26734 was published on 2023-10-23 and last updated on 2026-06-17.

CVE-2021-26734

CVE-2021-26734 is a medium-severity vulnerability in Zscaler Client Connector with a CVSS 3.x base score of 4.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-269.

Key facts

Severity: Medium (CVSS 3.x base score 4.4)
EPSS exploit prediction: 0% (4th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-269
Affected product: Zscaler Client Connector
Published: 2023-10-23
Last modified: 2026-06-17

Description

Zscaler Client Connector Installer on Windows before version 3.4.0.124 improperly handled directory junctions during uninstallation. A local adversary may be able to delete folders in an elevated context.

Frequently asked questions

What is CVE-2021-26734?: Zscaler Client Connector Installer on Windows before version 3.4.0.124 improperly handled directory junctions during uninstallation. A local adversary may be able to delete folders in an elevated context.
How severe is CVE-2021-26734?: CVE-2021-26734 has a CVSS 3.x base score of 4.4, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-26734 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26734?: CVE-2021-26734 affects Zscaler Client Connector. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-26734?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-26734 published?: CVE-2021-26734 was published on 2023-10-23 and last updated on 2026-06-17.

References

https://help.zscaler.com/zscaler-client-connector/client-connector-app-release-summary-2021

Affected products (1)

cpe:2.3:a:zscaler:client_connector:*:*:*:*:*:windows:*:*

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