CVE-2020-11633

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-07-15 · updated 2026-06-17
Weakness: CWE-787

Description

The Zscaler Client Connector for Windows prior to 2.1.2.74 had a stack based buffer overflow when connecting to misconfigured TLS servers. An adversary would potentially have been able to execute arbitrary code with system privileges.

Affected products

Zscaler Client Connector: before 2.1.2.81 — fixed in 2.1.2.81

How to fix

Upgrade to a fixed version: Zscaler Client Connector 2.1.2.81. Check the vendor advisory for mitigations.

References

https://help.zscaler.com/zscaler-client-connector/client-connector-app-release-summary-2020?applicable_category=Windows&applicable_version=2.1.2.81
https://help.zscaler.com/zscaler-client-connector/client-connector-app-release-summary-2020?applicable_category=Windows&applicable_version=2.1.2.81

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