How severe is CVE-2021-26736?

CVE-2021-26736 has a CVSS 3.x base score of 6.7, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-26736 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-26736?

CVE-2021-26736 affects Zscaler Client Connector. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-26736?

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

When was CVE-2021-26736 published?

CVE-2021-26736 was published on 2023-10-23 and last updated on 2026-06-17.

CVE-2021-26736

CVE-2021-26736 is a medium-severity vulnerability in Zscaler Client Connector with a CVSS 3.x base score of 6.7. 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-22.

Key facts

Severity: Medium (CVSS 3.x base score 6.7)
EPSS exploit prediction: 0% (13th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-22
Affected product: Zscaler Client Connector
Published: 2023-10-23
Last modified: 2026-06-17

Description

Multiple vulnerabilities in the Zscaler Client Connector Installer and Uninstaller for Windows prior to 3.6 allowed execution of binaries from a low privileged path. A local adversary may be able to execute code with SYSTEM privileges.

Frequently asked questions

What is CVE-2021-26736?: Multiple vulnerabilities in the Zscaler Client Connector Installer and Uninstaller for Windows prior to 3.6 allowed execution of binaries from a low privileged path. A local adversary may be able to execute code with SYSTEM privileges.
How severe is CVE-2021-26736?: CVE-2021-26736 has a CVSS 3.x base score of 6.7, rated medium severity. It is exploitable over local access with high attack complexity, requires low privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-26736 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (13th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-26736?: CVE-2021-26736 affects Zscaler Client Connector. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-26736?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-26736 published?: CVE-2021-26736 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:*:*

More vulnerabilities in Zscaler Client Connector

CVE-2020-11633 — Critical (CVSS 9.8): The Zscaler Client Connector for Windows prior to 2.1.2.74 had a stack based buffer overflow when connecting to…
CVE-2024-23463 — High (CVSS 8.8): Anti-tampering protection of the Zscaler Client Connector can be bypassed under certain conditions when running the…
CVE-2023-28804 — High (CVSS 8.2): An Improper Verification of Cryptographic Signature vulnerability in Zscaler Client Connector on Linux allows replacing…
CVE-2023-28799 — High (CVSS 8.2): A URL parameter during login flow was vulnerable to injection. An attacker could insert a malicious domain in this…
CVE-2023-28800 — High (CVSS 8.1): When using local accounts for administration, the redirect url parameter was not encoded correctly, allowing for an XSS…
CVE-2024-23456 — High (CVSS 7.8): Anti-tampering can be disabled under certain conditions without signature validation. This affects Zscaler Client…

All CVEs affecting Zscaler Client Connector →

Other CWE-22 (Path Traversal) vulnerabilities

CVE-2026-48282 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Limitation of a Pathname to a Restricted…
CVE-2026-54917 — Critical (CVSS 10.0): SeaweedFS is a distributed storage system for object storage (S3), file systems, and Iceberg tables. Prior to 4.30, the…
CVE-2026-11429 — Critical (CVSS 10.0): Two endpoints in the Vault Service ScriptsController, shared by Altium Enterprise Server and Altium 365, accept file…
CVE-2026-34909 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit a Path Traversal vulnerability found in UniFi OS devices to…
CVE-2026-7411 — Critical (CVSS 10.0): In Eclipse BaSyx Java Server SDK versions prior to 2.0.0-milestone-10, inadequate path normalization in the Submodel…
CVE-2026-36767 — Critical (CVSS 10.0): A path traversal vulnerability in the /content/images/add endpoint of shopizer v3.2.5 allows attackers write arbitrary…

Browse all CWE-22 (Path Traversal) vulnerabilities →